Method for transmitting or receiving physical downlink shared channel in wireless communication system and device therefor

ABSTRACT

A method for receiving a physical downlink shared channel (PDSCH) by a user equipment (UE) in a wireless communication system and device therefor is disclosed in the present disclosure.Particularly, a method for receiving a physical downlink shared channel (PDSCH) by a user equipment (UE) in a wireless communication system, the method according to an embodiment of the present disclosure comprising: receiving downlink control information (DCI); wherein the DCI includes i) a transmission configuration indication (TCI) field and ii) an antenna port field; and receiving the PDSCH scheduled based on the DCI, wherein a plurality of TCI states are indicated based on the TCI field, and demodulation reference signal (DM-RS) ports of a plurality of code division multiplexing (CDM) groups are indicated based on the antenna port field, and wherein a first TCI state among the plurality of TCI states corresponds to a CDM group including a first DM-RS port based on an instruction order of the DM-RS ports.

TECHNICAL FIELD

The present disclosure relates to a wireless communication system, andmore particularly, a method for transmitting and receiving a PhysicalDownlink Shared Channel (PDSCH) for improving reliability based onmultiple Transmission Reception Points (TRPs) and a device therefor.

BACKGROUND ART

Mobile communication systems have been developed to guarantee useractivity while providing voice services. Mobile communication systemsare expanding their services from voice only to data. Current soaringdata traffic is depleting resources and users' demand for higher-datarate services is leading to the need for more advanced mobilecommunication systems.

Next-generation mobile communication systems are required to meet, e.g.,handling of explosively increasing data traffic, significant increase inper-user transmission rate, working with a great number of connectingdevices, and support for very low end-to-end latency and high-energyefficiency. To that end, various research efforts are underway forvarious technologies, such as dual connectivity, massive multiple inputmultiple output (MIMO), in-band full duplex, non-orthogonal multipleaccess (NOMA), super wideband support, and device networking.

DISCLOSURE Technical Problem

The present disclosure proposes a method for transmitting and receivinga Physical Downlink Shared Channel (PDSCH) performed by a User Equipment(UE) supported by multiple Transmission Reception Points (TRPs) in awireless communication system.

Particularly, the present disclosure proposes a method for multiple TRPsto configure a transmission and reception operation of PDSCH forimproving reliability.

Furthermore, the present disclosure proposes a method for defining aDMRS table which may be referenced in transmission and receptionoperation of PDSCH for improving reliability.

Furthermore, considering a situation in which multiple users (e.g., UEs)operate together, the present disclosure proposes a method for multipleusers to use a DMRS port for a single user.

Furthermore, the present disclosure proposes a method for mapping a TCLstate to a CDM group or a DMRS port.

Furthermore, the present disclosure proposes a method for determining aport number of PTRS.

Technical problems to be solved by the present disclosure are notlimited by the above-mentioned technical problems, and other technicalproblems which are not mentioned above can be clearly understood fromthe following description by those skilled in the art to which thepresent disclosure pertains.

Technical Solution

A method for receiving a physical downlink shared channel (PDSCH) by auser equipment (UE) in a wireless communication system, the methodaccording to an embodiment of the present disclosure comprising:receiving downlink control information (DCI); wherein the DCI includesi) a transmission configuration indication (TCI) field and ii) anantenna port field; and receiving the PDSCH scheduled based on the DCI,wherein a plurality of TCI states are indicated based on the TCI field,and demodulation reference signal (DM-RS) ports of a plurality of codedivision multiplexing (CDM) groups are indicated based on the antennaport field, and wherein a first TCI state among the plurality of TCIstates corresponds to a CDM group including a first DM-RS port based onan instruction order of the DM-RS ports.

Furthermore, in the method according to an embodiment of the presentdisclosure, wherein based on the instruction order of the DMRS ports, anorder of the plurality of CDM groups is determined.

Furthermore, in the method according to an embodiment of the presentdisclosure, wherein a TCI state other than the first TCI statecorresponds to another CDM group other than a CDM group including thefirst DM-RS port.

Furthermore, in the method according to an embodiment of the presentdisclosure, wherein the PDSCH includes two codewords, wherein a numberof DM-RS ports of the CDM group including the first DM-RS port and anumber of DM-RS ports of the another CDM group are set to a specificnumber determined based on a total number of layers.

Furthermore, in the method according to an embodiment of the presentdisclosure, wherein a number of layers associated with each CDM group isset differently.

Furthermore, in the method according to an embodiment of the presentdisclosure, wherein layers are mapped based on indexes of the DM-RSports regardless of the instruction order of the DM-RS ports.

Furthermore, in the method according to an embodiment of the presentdisclosure, wherein based the DCI being associated with a Modulation andCoding Scheme (MCS)-C-RNTI, the DM-RS ports correspond to a same TCIstate.

Furthermore, in the method according to an embodiment of the presentdisclosure, further comprising: receiving information indicating thatthe DM-RS ports can be used by other terminals.

Furthermore, in the method according to an embodiment of the presentdisclosure, wherein the PDSCH is transmitted after a specific offsetfrom a transmission time of the DCI, and wherein DM-RS ports included inthe CDM group including the first DM-RS port are in QCL (Quasi colocation) relationship with a reference signal related to the first TCIstate.

Furthermore, a user equipment (UE) receiving a physical downlink sharedchannel (PDSCH) in a wireless communication system, the UE according toan embodiment of the present disclosure comprising: one or moretransceivers; one or more processors; and one or more memories forstoring instructions for operations executed by the one or moreprocessors and being coupled to the one or more processors; wherein theoperations comprises: receiving downlink control information (DCI);wherein the DCI includes i) a transmission configuration indication(TCI) field and ii) an antenna port field; and receiving the PDSCHscheduled based on the DCI, wherein a plurality of TCI states areindicated based on the TCI field, and demodulation reference signal(DM-RS) ports of a plurality of code division multiplexing (CDM) groupsare indicated based on the antenna port field, and wherein a first TCIstate among the plurality of TCI states corresponds to a CDM groupincluding a first DM-RS port based on an instruction order of the DM-RSports.

Furthermore, a method for transmitting a physical downlink sharedchannel (PDSCH) by a base station in a wireless communication system,the method according to an embodiment of the present disclosurecomprising: transmitting downlink control information (DCI); wherein theDCI includes i) a transmission configuration indication (TCI) field andii) an antenna port field; and transmitting the PDSCH scheduled based onthe DCI, wherein a plurality of TCI states are indicated based on theTCI field, and demodulation reference signal (DM-RS) ports of aplurality of code division multiplexing (CDM) groups are indicated basedon the antenna port field, and wherein a first TCI state among theplurality of TCI states corresponds to a CDM group including a firstDM-RS port based on an instruction order of the DM-RS ports.

Furthermore, a base station for transmitting a physical downlink sharedchannel (PDSCH) in a wireless communication system, the base stationaccording to an embodiment of the present disclosure comprising: one ormore transceivers; one or more processors; and one or more memories forstoring instructions for operations executed by the one or moreprocessors and being coupled to the one or more processors; wherein theoperations comprises: transmitting downlink control information (DCI);wherein the DCI includes i) a transmission configuration indication(TCI) field and ii) an antenna port field; and transmitting the PDSCHscheduled based on the DCI, wherein a plurality of TCI states areindicated based on the TCI field, and demodulation reference signal(DM-RS) ports of a plurality of code division multiplexing (CDM) groupsare indicated based on the antenna port field, and wherein a first TCIstate among the plurality of TCI states corresponds to a CDM groupincluding a first DM-RS port based on an instruction order of the DM-RSports.

Furthermore, an apparatus comprising one or more memories and one ormore processors operatively coupled to the one or more memories, theapparatus according to an embodiment of the present disclosurecomprising: wherein the one or more processors controls the apparatusto: receive downlink control information (DCI); wherein the DCI includesi) a transmission configuration indication (TCI) field and ii) anantenna port field; and receive the PDSCH scheduled based on the DCI,wherein a plurality of TCI states are indicated based on the TCI field,and demodulation reference signal (DM-RS) ports of a plurality of codedivision multiplexing (CDM) groups are indicated based on the antennaport field, and wherein a first TCI state among the plurality of TCIstates corresponds to a CDM group including a first DM-RS port based onan instruction order of the DM-RS ports.

Furthermore, one or more non-transitory computer-readable media storingone or more instructions, the one or more instructions executable by oneor more processors according to an embodiment of the present disclosurecomprising: an instruction indicates a user equipment (UE) to: receivedownlink control information (DCI); wherein the DCI includes i) atransmission configuration indication (TCI) field and ii) an antennaport field; and receive the PDSCH scheduled based on the DCI, wherein aplurality of TCI states are indicated based on the TCI field, anddemodulation reference signal (DM-RS) ports of a plurality of codedivision multiplexing (CDM) groups are indicated based on the antennaport field, and wherein a first TCI state among the plurality of TCIstates corresponds to a CDM group including a first DM-RS port based onan instruction order of the DM-RS ports.

Advantageous Effects

According to an embodiment of the present disclosure, PDSCH may betransmitted and received based on multiple Transmission Reception Points(TRPs).

Furthermore, according to an embodiment of the present disclosure,either one of operation that multiple TRPs performs an eMBB transmissionor a URLLC transmission for improving reliability may be set to a UserEquipment (UE).

Furthermore, according to an embodiment of the present disclosure, aDMRS table which may be referenced in a URLLC transmission may bedefined, and a bit width for indicating a DMRS table may be decreased,and accordingly, signaling overhead may be improved.

Furthermore, according to an embodiment of the present disclosure, aDMRS port for a single user may be configured to be usable by multipleusers, and resources may be efficiently used.

Furthermore, according to an embodiment of the present disclosure, anambiguity for a mapping relation between a TCL state and a CDM group orDMRS port may be removed.

Furthermore, according to an embodiment of the present disclosure, aport number of PTRS is optimally determined according to a configurationof a base station or TRP.

Effects obtainable from the present disclosure are not limited by theeffects mentioned above, and other effects which are not mentioned abovecan be clearly understood from the following description by thoseskilled in the art to which the present disclosure pertains.

DESCRIPTION OF DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the present disclosure and constitute a part of thedetailed description, illustrate embodiments of the present disclosureand together with the description serve to explain the principle of thepresent disclosure.

FIG. 1 is a diagram illustrating an example of an overall systemstructure of NR to which a method proposed in the present disclosure maybe applied.

FIG. 2 illustrates a relationship between an uplink frame and a downlinkframe in a wireless communication system to which a method proposed inthe present disclosure may be applied.

FIG. 3 illustrates an example of a frame structure in an NR system.

FIG. 4 illustrates an example of a resource grid supported by a wirelesscommunication system to which a method proposed in the presentdisclosure may be applied.

FIG. 5 illustrates examples of a resource grid for each antenna port andnumerology to which a method proposed in the present disclosure may beapplied.

FIG. 6 illustrates physical channels and general signal transmissionused in a 3GPP system.

FIG. 7 is a diagram illustration an example of downlinktransmission/reception operation.

FIG. 8 illustrates an example of uplink transmission/receptionoperation.

FIG. 9 is a flowchart illustrating an example of DL DMRS procedure.

FIG. 10 is a flowchart illustrating an example of a CSI relatedprocedure.

FIG. 11 illustrates a transmission and reception method for reliabilityimprovement supported by multiple TRPs, and the following two methodsmay be considered.

FIG. 12 illustrates an example of a message (e.g., MAC CE) foractivation/deactivation of TCI states for UE-specific PDSCH MAC CEdefined in TS38.321.

FIG. 13 illustrates an example of the signaling procedure of performingdata transmission/reception between a Network side and a UE in asituation of multiple TRPs to which the method and/or embodimentsproposed in the present disclosure may be applied.

FIG. 14 illustrates an example of PTRS reception operation flowchart ofa User Equipment (UE) to which the method (e.g., Proposal 1/2/3/4/5,etc.) proposed in the present disclosure may be applied.

FIG. 15 illustrates an example of data transmission/reception operationflowchart of a Base Station (BS) to which the methods (e.g., Proposal1/2/3/4/5, etc.) proposed in the present disclosure may be applied.

FIG. 16 illustrates a communication system applied to the presentdisclosure.

FIG. 17 illustrates a wireless device which may be applied to thepresent disclosure.

FIG. 18 illustrates a signal processing circuit for a transmit signal.

FIG. 19 illustrates another example of a wireless device applied to thepresent disclosure.

FIG. 20 illustrates a hand-held device applied to the presentdisclosure.

MODE FOR DISCLOSURE

Reference will now be made in detail to embodiments of the disclosure,examples of which are illustrated in the accompanying drawings. Adetailed description to be disclosed below together with theaccompanying drawing is to describe exemplary embodiments of the presentdisclosure and not to describe a unique embodiment for carrying out thepresent disclosure. The detailed description below includes details toprovide a complete understanding of the present disclosure. However,those skilled in the art know that the present disclosure can be carriedout without the details.

In some cases, in order to prevent a concept of the present disclosurefrom being ambiguous, known structures and devices may be omitted orillustrated in a block diagram format based on core functions of eachstructure and device.

Hereinafter, downlink (DL) means communication from the base station tothe terminal and uplink (UL) means communication from the terminal tothe base station. In downlink, a transmitter may be part of the basestation, and a receiver may be part of the terminal. In uplink, thetransmitter may be part of the terminal and the receiver may be part ofthe base station. The base station may be expressed as a firstcommunication device and the terminal may be expressed as a secondcommunication device. A base station (BS) may be replaced with termsincluding a fixed station, a Node B, an evolved-NodeB (eNB), a NextGeneration NodeB (gNB), a base transceiver system (BTS), an access point(AP), a network (5G network), an AI system, a road side unit (RSU), avehicle, a robot, an Unmanned Aerial Vehicle (UAV), an Augmented Reality(AR) device, a Virtual Reality (VR) device, and the like. Further, theterminal may be fixed or mobile and may be replaced with terms includinga User Equipment (UE), a Mobile Station (MS), a user terminal (UT), aMobile Subscriber Station (MSS), a Subscriber Station (SS), an AdvancedMobile Station (AMS), a Wireless Terminal (WT), a Machine-TypeCommunication (MTC) device, a Machine-to-Machine (M2M) device, and aDevice-to-Device (D2D) device, the vehicle, the robot, an AI module, theUnmanned Aerial Vehicle (UAV), the Augmented Reality (AR) device, theVirtual Reality (VR) device, and the like.

The following technology may be used in various radio access systemincluding CDMA, FDMA, TDMA, OFDMA, SC-FDMA, and the like. The CDMA maybe implemented as radio technology such as Universal Terrestrial RadioAccess (UTRA) or CDMA2000. The TDMA may be implemented as radiotechnology such as a global system for mobile communications(GSM)/general packet radio service (GPRS)/enhanced data rates for GSMevolution (EDGE). The OFDMA may be implemented as radio technology suchas Institute of Electrical and Electronics Engineers (IEEE) 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Evolved UTRA (E-UTRA), or thelike. The UTRA is a part of Universal Mobile Telecommunications System(UMTS). 3rd Generation Partnership Project (3GPP) Long Term Evolution(LTE) is a part of Evolved UMTS (E-UMTS) using the E-UTRA andLTE-Advanced (A)/LTE-A pro is an evolved version of the 3GPP LTE. 3GPPNR (New Radio or New Radio Access Technology) is an evolved version ofthe 3GPP LTE/LTE-A/LTE-A pro.

For clarity of description, the technical spirit of the presentdisclosure is described based on the 3GPP communication system (e.g.,LTE-A or NR), but the technical spirit of the present disclosure are notlimited thereto. LTE means technology after 3GPP TS 36.xxx Release 8. Indetail, LTE technology after 3GPP TS 36.xxx Release 10 is referred to asthe LTE-A and LTE technology after 3GPP TS 36.xxx Release 13 is referredto as the LTE-A pro. The 3GPP NR means technology after TS 38.xxxRelease 15. The LTE/NR may be referred to as a 3GPP system. “xxx” meansa standard document detail number. Matters disclosed in a standarddocument opened before the present disclosure may be referred to for abackground art, terms, abbreviations, etc., used for describing thepresent disclosure. For example, the following documents may be referredto.

3GPP LTE

-   -   36.211: Physical channels and modulation    -   36.212: Multiplexing and channel coding    -   36.213: Physical layer procedures    -   36.300: Overall description    -   36.331: Radio Resource Control (RRC)

3GPP NR

-   -   38.211: Physical channels and modulation    -   38.212: Multiplexing and channel coding    -   38.213: Physical layer procedures for control    -   38.214: Physical layer procedures for data    -   38.300: NR and NG-RAN Overall Description    -   36.331: Radio Resource Control (RRC) protocol specification

As more and more communication devices require larger communicationcapacity, there is a need for improved mobile broadband communicationcompared to the existing radio access technology (RAT). Further, massivemachine type communications (MTCs), which provide various servicesanytime and anywhere by connecting many devices and objects, are one ofthe major issues to be considered in the next generation communication.In addition, a communication system design considering a service/UEsensitive to reliability and latency is being discussed. Theintroduction of next generation radio access technology consideringenhanced mobile broadband communication (eMBB), massive MTC (mMTC),ultra-reliable and low latency communication (URLLC) is discussed, andin the present disclosure, the technology is called new RAT forconvenience. The NR is an expression representing an example of 5G radioaccess technology (RAT).

Three major requirement areas of 5G include (1) an enhanced mobilebroadband (eMBB) area, (2) a massive machine type communication (mMTC)area and (3) an ultra-reliable and low latency communications (URLLC)area.

Some use cases may require multiple areas for optimization, and otheruse case may be focused on only one key performance indicator (KPI). 5Gsupport such various use cases in a flexible and reliable manner.

eMBB is far above basic mobile Internet access and covers media andentertainment applications in abundant bidirectional tasks, cloud oraugmented reality. Data is one of key motive powers of 5G, and dedicatedvoice services may not be first seen in the 5G era. In 5G, it isexpected that voice will be processed as an application program using adata connection simply provided by a communication system. Major causesfor an increased traffic volume include an increase in the content sizeand an increase in the number of applications that require a high datatransfer rate. Streaming service (audio and video), dialogue type videoand mobile Internet connections will be used more widely as more devicesare connected to the Internet. Such many application programs requireconnectivity always turned on in order to push real-time information andnotification to a user. A cloud storage and application suddenlyincreases in the mobile communication platform, and this may be appliedto both business and entertainment. Furthermore, cloud storage is aspecial use case that tows the growth of an uplink data transfer rate.5G is also used for remote business of cloud. When a tactile interfaceis used, further lower end-to-end latency is required to maintainexcellent user experiences. Entertainment, for example, cloud game andvideo streaming are other key elements which increase a need for themobile broadband ability. Entertainment is essential in the smartphoneand tablet anywhere including high mobility environments, such as atrain, a vehicle and an airplane. Another use case is augmented realityand information search for entertainment. In this case, augmentedreality requires very low latency and an instant amount of data.

Furthermore, one of the most expected 5G use case relates to a functioncapable of smoothly connecting embedded sensors in all fields, that is,mMTC. Until 2020, it is expected that potential IoT devices will reach20.4 billions. The industry IoT is one of areas in which 5G performsmajor roles enabling smart city, asset tracking, smart utility,agriculture and security infra.

URLLC includes a new service which will change the industry throughremote control of major infra and a link having ultra reliability/lowavailable latency, such as a self-driving vehicle. A level ofreliability and latency is essential for smart grid control, industryautomation, robot engineering, drone control and adjustment.

Multiple use cases are described more specifically.

5G may supplement fiber-to-the-home (FTTH) and cable-based broadband (orDOCSIS) as means for providing a stream evaluated from gigabits persecond to several hundreds of mega bits per second. Such fast speed isnecessary to deliver TV with resolution of 4K or more (6K, 8K or more)in addition to virtual reality and augmented reality. Virtual reality(VR) and augmented reality (AR) applications include immersive sportsgames. A specific application program may require a special networkconfiguration. For example, in the case of VR game, in order for gamecompanies to minimize latency, a core server may need to be integratedwith the edge network server of a network operator.

An automotive is expected to be an important and new motive power in 5G,along with many use cases for the mobile communication of an automotive.For example, entertainment for a passenger requires a high capacity anda high mobility mobile broadband at the same time. The reason for thisis that future users continue to expect a high-quality connectionregardless of their location and speed. Another use example of theautomotive field is an augmented reality dashboard. The augmentedreality dashboard overlaps and displays information, identifying anobject in the dark and notifying a driver of the distance and movementof the object, over a thing seen by the driver through a front window.In the future, a wireless module enables communication betweenautomotives, information exchange between an automotive and a supportedinfrastructure, and information exchange between an automotive and otherconnected devices (e.g., devices accompanied by a pedestrian). A safetysystem guides alternative courses of a behavior so that a driver candrive more safely, thereby reducing a danger of an accident. A next stepwill be a remotely controlled or self-driven vehicle. This requires veryreliable, very fast communication between different self-driven vehiclesand between an automotive and infra. In the future, a self-drivenvehicle may perform all driving activities, and a driver will be focusedon things other than traffic, which cannot be identified by anautomotive itself. Technical requirements of a self-driven vehiclerequire ultra-low latency and ultra-high speed reliability so thattraffic safety is increased up to a level which cannot be achieved by aperson.

A smart city and smart home mentioned as a smart society will beembedded as a high-density radio sensor network. The distributed networkof intelligent sensors will identify the cost of a city or home and acondition for energy-efficient maintenance. A similar configuration maybe performed for each home. All of a temperature sensor, a window andheating controller, a burglar alarm and home appliances are wirelesslyconnected. Many of such sensors are typically a low data transfer rate,low energy and a low cost. However, for example, real-time HD video maybe required for a specific type of device for surveillance.

The consumption and distribution of energy including heat or gas arehighly distributed and thus require automated control of a distributedsensor network. A smart grid collects information, and interconnectssuch sensors using digital information and a communication technology sothat the sensors operate based on the information. The information mayinclude the behaviors of a supplier and consumer, and thus the smartgrid may improve the distribution of fuel, such as electricity, in anefficient, reliable, economical, production-sustainable and automatedmanner. The smart grid may be considered to be another sensor networkhaving small latency.

A health part owns many application programs which reap the benefits ofmobile communication. A communication system can support remotetreatment providing clinical treatment at a distant place. This helps toreduce a barrier for the distance and can improve access to medicalservices which are not continuously used at remote farming areas.Furthermore, this is used to save life in important treatment and anemergency condition. A radio sensor network based on mobilecommunication can provide remote monitoring and sensors for parameters,such as the heart rate and blood pressure.

Radio and mobile communication becomes increasingly important in theindustry application field. Wiring requires a high installation andmaintenance cost. Accordingly, the possibility that a cable will bereplaced with reconfigurable radio links is an attractive opportunity inmany industrial fields. However, to achieve the possibility requiresthat a radio connection operates with latency, reliability and capacitysimilar to those of the cable and that management is simplified. Lowlatency and a low error probability is a new requirement for aconnection to 5G.

Logistics and freight tracking is an important use case for mobilecommunication, which enables the tracking inventory and packagesanywhere using a location-based information system. The logistics andfreight tracking use case typically requires a low data speed, but awide area and reliable location information.

In a new RAT system including NR uses an OFDM transmission scheme or asimilar transmission scheme thereto. The new RAT system may follow OFDMparameters different from OFDM parameters of LTE. Alternatively, the newRAT system may follow numerology of conventional LTE/LTE-A as it is orhave a larger system bandwidth (e.g., 100 MHz). Alternatively, one cellmay support a plurality of numerologies. In other words, UEs thatoperate with different numerologies may coexist in one cell.

The numerology corresponds to one subcarrier spacing in a frequencydomain. Different numerologies may be defined by scaling referencesubcarrier spacing to an integer N.

Definition of Terms

eLTE eNB: The eLTE eNB is the evolution of eNB that supportsconnectivity to EPC and NGC.

gNB: A node which supports the NR as well as connectivity to NGC.

New RAN: A radio access network which supports either NR or E-UTRA orinterfaces with the NGC.

Network slice: A network slice is a network created by the operatorcustomized to provide an optimized solution for a specific marketscenario which demands specific requirements with end-to-end scope.

Network function: A network function is a logical node within a networkinfrastructure that has well-defined external interfaces andwell-defined functional behaviour.

NG-C: A control plane interface used on NG2 reference points between newRAN and NGC.

NG-U: A user plane interface used on NG3 references points between newRAN and NGC.

Non-standalone NR: A deployment configuration where the gNB requires anLTE eNB as an anchor for control plane connectivity to EPC, or requiresan eLTE eNB as an anchor for control plane connectivity to NGC.

Non-standalone E-UTRA: A deployment configuration where the eLTE eNBrequires a gNB as an anchor for control plane connectivity to NGC.

User plane gateway: A termination point of NG-U interface.

Overview of System

FIG. 1 illustrates an example of an overall structure of a NR system towhich a method proposed in the present disclosure is applicable.

Referring to FIG. 1, an NG-RAN consists of gNBs that provide an NG-RAuser plane (new AS sublayer/PDCP/RLC/MAC/PHY) and control plane (RRC)protocol terminations for a user equipment (UE).

The gNBs are interconnected with each other by means of an Xn interface.

The gNBs are also connected to an NGC by means of an NG interface.

More specifically, the gNBs are connected to an access and mobilitymanagement function (AMF) by means of an N2 interface and to a userplane function (UPF) by means of an N3 interface.

New RAT (NR) Numerology and Frame Structure

In the NR system, multiple numerologies may be supported. Thenumerologies may be defined by subcarrier spacing and a CP (CyclicPrefix) overhead. Spacing between the plurality of subcarriers may bederived by scaling basic subcarrier spacing into an integer N (or μ). Inaddition, although a very low subcarrier spacing is assumed not to beused at a very high subcarrier frequency, a numerology to be used may beselected independent of a frequency band.

In addition, in the NR system, a variety of frame structures accordingto the multiple numerologies may be supported.

Hereinafter, an orthogonal frequency division multiplexing (OFDM)numerology and a frame structure, which may be considered in the NRsystem, will be described.

A plurality of OFDM numerologies supported in the NR system may bedefined as in Table 1.

TABLE 1 μ Δf = 2^(μ) ·15 [kHz] Cyclic prefix 0 15 Normal 1 30 Normal 260 Normal, Extended 3 120 Normal 4 240 Normal

The NR supports multiple numerologies (or subcarrier spacing (SCS)) forsupporting various 5G services. For example, when the SCS is 15 kHz, awide area in traditional cellular bands is supported and when the SCS is30 kHz/60 kHz, dense-urban, lower latency, and wider carrier bandwidthare supported, and when the SCS is 60 kHz or higher there than, abandwidth larger than 24.25 GHz is supported in order to overcome phasenoise.

An NR frequency band is defined as frequency ranges of two types (FR1and FR2). FR1 and FR2 may be configured as shown in Table 2 below.Further, FR2 may mean a millimeter wave (mmW).

TABLE 2 Frequency Range Corresponding frequency Subcarrier designationrange Spacing FR1  410 MHz-7125 MHz 15, 30, 60 kHz FR2 24250 MHz-52600MHz 60, 120, 240 kHz

Regarding a frame structure in the NR system, a size of various fieldsin the time domain is expressed as a multiple of a time unit ofT_(s)=1/(Δf_(max)·N_(f)). In this case, Δf_(max)=480·10³, andN_(f)=4096. DL and UL transmission is configured as a radio frame havinga section of T_(f)=(Δf_(max)N_(f)/100)·T_(s)=10 ms. The radio frame iscomposed of ten subframes each having a section ofT_(sf)=(Δf_(max)N_(f)/1000)·T_(s)=1 ms. In this case, there may be a setof UL frames and a set of DL frames.

FIG. 2 illustrates a relation between an uplink frame and a downlinkframe in a wireless communication system to which a method proposed inthe present disclosure is applicable.

As illustrated in FIG. 2, uplink frame number i for transmission from auser equipment (UE) shall start T_(TA)=N_(TA)T_(s) before the start of acorresponding downlink frame at the corresponding UE.

Regarding the numerology μ, slots are numbered in increasing order ofn_(s) ^(μ)∈{0, . . . , N_(subframe) ^(slots, μ)−1} within a subframe andare numbered in increasing order of n_(s,f) ^(μ)∈{0, . . . , N_(frame)^(slots,μ)−1} within a radio frame. One slot consists of consecutiveOFDM symbols of N_(symb) ^(μ), and N_(symb) ^(μ) is determined dependingon a numerology used and slot configuration. The start of slots n_(s)^(μ) in a subframe is aligned in time with the start of OFDM symbolsn_(s) ^(μ)N_(symb) ^(μ) in the same subframe.

Not all UEs are able to transmit and receive at the same time, and thismeans that not all OFDM symbols in a downlink slot or an uplink slot areavailable to be used.

Table 3 represents the number N_(symb) ^(slot) of OFDM symbols per slot,the number N_(slot) ^(frame,μ) of slots per radio frame, and the numberN_(slot) ^(subframe, μ) of slots per subframe in a normal CP. Table 4represents the number of OFDM symbols per slot, the number of slots perradio frame, and the number of slots per subframe in an extended CP.

TABLE 3 μ N_(symb) ^(slot) N_(slot) ^(frame,μ) N_(slot) ^(subframe,μ) 014 10 1 1 14 20 2 2 14 40 4 3 14 80 8 4 14 160  16 

TABLE 4 μ N_(symb) ^(slot) N_(slot) ^(frame,μ) N_(slot) ^(subframe,μ) 212 40 4

FIG. 3 illustrates an example of a frame structure in a NR system. FIG.3 is merely for convenience of explanation and does not limit the scopeof the present disclosure.

In Table 4, in case of μ=2, i.e., as an example in which a subcarrierspacing (SCS) is 60 kHz, one subframe (or frame) may include four slotswith reference to Table 3, and one subframe={1, 2, 4} slots shown inFIG. 3, for example, the number of slot(s) that may be included in onesubframe may be defined as in Table 3.

Further, a mini-slot may consist of 2, 4, or 7 symbols, or may consistof more symbols or less symbols.

In regard to physical resources in the NR system, an antenna port, aresource grid, a resource element, a resource block, a carrier part,etc. may be considered.

Hereinafter, the above physical resources that can be considered in theNR system are described in more detail.

First, in regard to an antenna port, the antenna port is defined so thata channel over which a symbol on an antenna port is conveyed can beinferred from a channel over which another symbol on the same antennaport is conveyed. When large-scale properties of a channel over which asymbol on one antenna port is conveyed can be inferred from a channelover which a symbol on another antenna port is conveyed, the two antennaports may be regarded as being in a quasi co-located or quasico-location (QC/QCL) relation. Here, the large-scale properties mayinclude at least one of delay spread, Doppler spread, frequency shift,average received power, and received timing.

FIG. 4 illustrates an example of a resource grid supported in a wirelesscommunication system to which a method proposed in the presentdisclosure is applicable.

Referring to FIG. 4, a resource grid consists of N_(RB) ^(μ)N_(sc) ^(RB)subcarriers on a frequency domain, each subframe consisting of 14·2μOFDM symbols, but the present disclosure is not limited thereto.

In the NR system, a transmitted signal is described by one or moreresource grids, consisting of N_(RB) ^(μ)N_(sc) ^(RB) subcarriers, and2^(μ)N_(symb) ^((μ)) OFDM symbols, where N_(RB) ^(μ)≤N_(RB) ^(max,μ).N_(RB) ^(max,μ) denotes a maximum transmission bandwidth and may changenot only between numerologies but also between uplink and downlink.

In this case, as illustrated in FIG. 5, one resource grid may beconfigured per numerology μ and antenna port p.

FIG. 5 illustrates examples of a resource grid per antenna port andnumerology to which a method proposed in the present disclosure isapplicable.

Each element of the resource grid for the numerology μ and the antennaport p is called a resource element and is uniquely identified by anindex pair (k,l) where k=0, . . . , N_(RB) ^(μ)N_(sc) ^(RB)−1 is anindex on a frequency domain, and l=0, . . . , 2^(μ)N_(symb) ^((μ))−1refers to a location of a symbol in a subframe. The index pair (k,l) isused to refer to a resource element in a slot, where l=0, . . . ,N_(symb) ^(μ)−1.

The resource element (k,l) for the numerology μ and the antenna port pcorresponds to a complex value a_(k,l) ^((p,μ)). When there is no riskfor confusion or when a specific antenna port or numerology is notspecified, the indexes p and μ may be dropped, and as a result, thecomplex value may be a_(k,l) ^((p)) or a_(k,l) .

Further, a physical resource block is defined as N_(sc) ^(RB)=12consecutive subcarriers in the frequency domain.

Point A serves as a common reference point of a resource block grid andmay be obtained as follows.

-   -   offsetToPointA for PCell downlink represents a frequency offset        between the point A and a lowest subcarrier of a lowest resource        block that overlaps a SS/PBCH block used by the UE for initial        cell selection, and is expressed in units of resource blocks        assuming 15 kHz subcarrier spacing for FR1 and 60 kHz subcarrier        spacing for FR2;    -   absoluteFrequencyPointA represents frequency-location of the        point A expressed as in absolute radio-frequency channel number        (ARFCN).

The common resource blocks are numbered from 0 and upwards in thefrequency domain for subcarrier spacing configuration μ.

The center of subcarrier 0 of common resource block 0 for the subcarrierspacing configuration μ coincides with ‘point A’. A common resourceblock number n_(CRB) ^(μ) in the frequency domain and resource elements(k, l) for the subcarrier spacing configuration μ may be given by thefollowing Equation 1.

$\begin{matrix}{n_{CRB}^{\mu} = \lfloor \frac{k}{N_{sc}^{RB}} \rfloor} & \lbrack {{Equation}\mspace{14mu} 1} \rbrack\end{matrix}$

Here, k may be defined relative to the point A so that k=0 correspondsto a subcarrier centered around the point A. Physical resource blocksare defined within a bandwidth part (BWP) and are numbered from 0 toN_(BWP,i) ^(size)−1 where i is No. of the BWP. A relation between thephysical resource block n_(PRB) in BWP i and the common resource blockn_(CRB) may be given by the following Equation 2.

n _(CRB) =n _(PRB) +N _(BWP,i) ^(start)  [Equation 2]

Here, N_(BWP,i) ^(start) may be the common resource block where the BWPstarts relative to the common resource block 0.

Physical Channel and General Signal Transmission

FIG. 6 illustrates physical channels and general signal transmissionused in a 3GPP system. In a wireless communication system, the UEreceives information from the eNB through Downlink (DL) and the UEtransmits information from the eNB through Uplink (UL). The informationwhich the eNB and the UE transmit and receive includes data and variouscontrol information and there are various physical channels according toa type/use of the information which the eNB and the UE transmit andreceive.

When the UE is powered on or newly enters a cell, the UE performs aninitial cell search operation such as synchronizing with the eNB (S601).To this end, the UE may receive a Primary Synchronization Signal (PSS)and a (Secondary Synchronization Signal (SSS) from the eNB andsynchronize with the eNB and acquire information such as a cell ID orthe like. Thereafter, the UE may receive a Physical Broadcast Channel(PBCH) from the eNB and acquire in-cell broadcast information.Meanwhile, the UE receives a Downlink Reference Signal (DL RS) in aninitial cell search step to check a downlink channel status.

A UE that completes the initial cell search receives a Physical DownlinkControl Channel (PDCCH) and a Physical Downlink Control Channel (PDSCH)according to information loaded on the PDCCH to acquire more specificsystem information (S602).

Meanwhile, when there is no radio resource first accessing the eNB orfor signal transmission, the UE may perform a Random Access Procedure(RACH) to the eNB (S603 to S606). To this end, the UE may transmit aspecific sequence to a preamble through a Physical Random Access Channel(PRACH) (S603 and S605) and receive a response message (Random AccessResponse (RAR) message) for the preamble through the PDCCH and acorresponding PDSCH. In the case of a contention based RACH, aContention Resolution Procedure may be additionally performed (S606).

The UE that performs the above procedure may then perform PDCCH/PDSCHreception (S607) and Physical Uplink Shared Channel (PUSCH)/PhysicalUplink Control Channel (PUCCH) transmission (S608) as a generaluplink/downlink signal transmission procedure. In particular, the UE mayreceive Downlink Control Information (DCI) through the PDCCH. Here, theDCI may include control information such as resource allocationinformation for the UE and formats may be differently applied accordingto a use purpose.

For example, in an NR system, DCI format 0_0 and DCI format 0_1 may beused for scheduling PUSCH in one cell, and DCI format 1_0 and DCI format1_1 may be used for scheduling PDSCH in one cell. Information includedin DCI format 0_0 is CRC-scrambled and transmitted by C-RNTI, CS-RNTI,or MCS-C-RNTI. In addition, DCI format 0_1 is used for reserving thePUSCH in one cell. Information included in DCI format 0_1 isCRC-scrambled and transmitted by C-RNTI, CS-RNTI, SP-CSI-RNTI, orMCS-C-RNTI. DCI format 1_0 is used for scheduling of the PDSCH in one DLcell. Information included in DCI format 1_0 is CRC-scrambled andtransmitted by C-RNTI, CS-RNTI, or MCS-C-RNTI. DCI format 1_1 is usedfor scheduling of the PDSCH in one cell. Information included in DCIformat 1_1 is CRC-scrambled and transmitted by C-RNTI, CS-RNTI, orMCS-C-RNTI. DCI format 2_1 is used to inform PRB(s) and OFDM symbol(s)of which the UE may assume not intending transmission. Informationincluded in DCI format 2_1 such as preemption indication 1, preemptionindication 2, . . . , preemption indication N, and the like isCRC-scrambled and transmitted by INT-RNTI.

Meanwhile, the control information which the UE transmits to the eNBthrough the uplink or the UE receives from the eNB may include adownlink/uplink ACK/NACK signal, a Channel Quality Indicator (CQI), aPrecoding Matrix Index (PMI), a Rank Indicator (RI), and the like. TheUE may transmit the control information such as the CQI/PMI/RI, etc.,through the PUSCH and/or PUCCH.

DL and UL Transmission/Reception Operation

Downlink Transmission/Reception Operation

FIG. 7 is a diagram illustration an example of downlinktransmission/reception operation.

Referring to FIG. 7, a BS schedules downlink transmission such as afrequency/time resource, a transport layer, a downlink precoder, MCS,and the like (step S701). In particular, the BS may determine a beam forPDSCH transmission to a UE through the above-described beam managementoperations. The UE receives Downlink Control Information (DCI) fordownlink scheduling (i.e., including scheduling information of thePDSCH) on the PDCCH from the BS (step S702). DCI format 1_0 or 1_1 maybe used for the downlink scheduling and in particular, DCI format 1_1includes the following information: Identifier for DCI formats,Bandwidth part indicator, Frequency domain resource assignment, Timedomain resource assignment, PRB bundling size indicator, Rate matchingindicator, ZP CSI-RS trigger, Antenna port(s), Transmissionconfiguration indication (TCI), SRS request, and Demodulation ReferenceSignal (DMRS) sequence initialization.

Particularly, according to each state indicated in an antenna port(s)field, the number of DMRS ports may be scheduled and in addition,Single-user (SU)/Multi-user (MU) transmission scheduling is alsoavailable. Furthermore, a TCI field is configured by 3 bits and amaximum of 8 TCI states are indicated according to a TCI field value todynamically the QCL for the DMRS. The UE receives downlink data from theBS on the PDSCH (step S703). When the UE detects a PDCCH including DCIformat 1_0 or 1_1, the UE decodes the PDSCH according to the indicationby the corresponding DCI.

Here, when the UE receives a PDSCH scheduled by DCI format 1_1, a DMRSconfiguration type may be configured by higher layer parameter‘dmrs-Type’ in the UE, and the DMRS type is used for receiving thePDSCH. Furthermore, in the UE, the maximum number of front-loaded DMRAsymbols for the PDSCH may be configured by higher layer parameter‘maxLength’.

In the case of DMRS configuration type 1, when a single codeword isscheduled and an antenna port mapped to an index of {2, 9, 10, 11, or30} is designated in the UE or when two codewords are scheduled in theUE, the UE assumes that all remaining orthogonal antenna ports are notassociated with PDSCH transmission to another UE. Alternatively, in thecase of DMRS configuration type 2, when a single codeword is scheduledand an antenna port mapped to an index of {2, 10, or 23} is designatedin the UE or when two codewords are scheduled in the UE, the UE assumesthat all remaining orthogonal antenna ports are not associated withPDSCH transmission to another UE.

When the UE receives the PDSCH, a precoding granularity P′ may beassumed as a consecutive resource block in the frequency domain. Here,P′ may correspond to one value of {2, 4, and wideband}. When P′ isdetermined as wideband, the UE does not predict that the PDSCH isscheduled to non-contiguous PRBs, and the UE may assume that the sameprecoding is applied to the allocated resource. On the contrary, when P′is determined as any one of {2 and 4}, a Precoding Resource Block Group(PRG) is split into P′ consecutive PRBs. The number of actuallyconsecutive PRBs in each PRG may be one or more. The UE may assume thatthe same precoding is applied to consecutive downlink PRBs in the PRG.

In order to determine a modulation order in the PDSCH, a target coderate, and a transport block size, the UE first reads a 5-bit MCD fieldin the DCI and determines the modulation order and the target code rate.In addition, the UE reads a redundancy version field in the DCI anddetermines a redundancy version. Furthermore, the UE determines thetransport block size by using the number of layers before rate matchingand the total number of allocated PRBs.

A transport block may be constructed with one or more code block groups(CBGs), and one CBG may be constructed with one or more code blocks(CBs). Furthermore, in an NR system, data transmission/reception in aCB/CBG unit as well as data transmission/reception in a transport blockunit but also may be available. Accordingly, the UE may receiveinformation on CB/CBG from the BS through DCI (e.g., DCI format 0_1, DCIformat 1_1, etc.). In addition, the UE may receive information on a datatransmission unit (e.g., TB/CB/CBG) from the BS.

Uplink Transmission/Reception Operation

FIG. 8 illustrates an example of uplink transmission/receptionoperation.

Referring to FIG. 8, a BS schedules uplink transmission such as thefrequency/time resource, the transport layer, an uplink precoder, theMCS, and the like (step S801). In particular, the BS may determine abeam for PUSCH transmission of the UE through the above-describedoperations. A UE receives DCI for downlink scheduling (i.e., includingscheduling information of the PUSCH) on the PDCCH (step S802). DCIformat 0_0 or 0_1 may be used for the uplink scheduling and inparticular, DCI format 0_1 includes the following information:Identifier for DCI formats, UL/Supplementary uplink (SUL) indicator,Bandwidth part indicator, Frequency domain resource assignment, Timedomain resource assignment, Frequency hopping flag, Modulation andcoding scheme (MCS), SRS resource indicator (SRI), Precoding informationand number of layers, Antenna port(s), SRS request, DMRS sequenceinitialization, and Uplink Shared Channel (UL-SCH) indicator.

Particularly, SRS resources configured in an SRS resource set associatedwith higher layer parameter ‘usage’ may be indicated by an SRS resourceindicator field. Further, ‘spatialRelationInfo’ may be configured foreach SRS resource and a value of ‘spatialRelationInfo’ may be one of{CRI, SSB, and SRI}.

Furthermore, the UE transmits the uplink data to the BS on the PUSCH(step S803). When the UE detects a PDCCH including DCI format 0_0 or0_1, the UE transmits the corresponding PUSCH according to theindication by the corresponding DCI. Two transmission schemes includinga codebook based transmission and a non-codebook based transmission aresupported for PUSCH transmission.

In the case of the codebook based transmission, when higher layerparameter txConfig′ is set to ‘codebook’, the UE is configured to thecodebook based transmission. On the contrary, when higher layerparameter txConfig′ is set to ‘nonCodebook’, the UE is configured to thenon-codebook based transmission. When higher layer parameter ‘txConfig’is not configured, the UE does not predict that the PUSCH is scheduledby DCI format 0_1. When the PUSCH is scheduled by DCI format 0_0, thePUSCH transmission is based on a single antenna port. In the case of thecodebook based transmission, the PUSCH may be scheduled by DCI format0_0, DCI format 0_1, or semi-statically. When the PUSCH is scheduled byDCI format 0_1, the UE determines a PUSCH transmission precoder based onthe SRI, the Transmit Precoding Matrix Indicator (TPMI), and thetransmission rank from the DCI as given by the SRS resource indicatorand the Precoding information and number of layers field. The TPMI isused for indicating a precoder to be applied over the antenna port andwhen multiple SRS resources are configured, the TPMI corresponds to theSRS resource selected by the SRI. Alternatively, when the single SRSresource is configured, the TPMI is used for indicating the precoder tobe applied over the antenna port and corresponds to the correspondingsingle SRS resource. A transmission precoder is selected from an uplinkcodebook having the same antenna port number as higher layer parameter‘nrofSRS-Ports’. When the UE is set to higher layer parameter ‘txConfig’set to ‘codebook’, at least one SRS resource is configured in the UE. AnSRI indicated in slot n is associated with most recent transmission ofthe SRS resource identified by the SRI and here, the SRS resourceprecedes PDCCH (i.e., slot n) carrying the SRI.

In the case of the non-codebook based transmission, the PUSCH may bescheduled by DCI format 0_0, DCI format 0_1, or semi-statically. Whenmultiple SRS resources are configured, the UE may determine the PUSCHprecoder and the transmission rank based on a wideband SRI and here, theSRI is given by the SRS resource indicator in the DCI or given by higherlayer parameter ‘srs-ResourceIndicator’. The UE may use one or multipleSRS resources for SRS transmission and here, the number of SRS resourcesmay be configured for simultaneous transmission in the same RB based onthe UE capability. Only one SRS port is configured for each SRSresource. Only one SRS resource may be configured to higher layerparameter ‘usage’ set to ‘nonCodebook’. The maximum number of SRSresources which may be configured for non-codebook based uplinktransmission is 4. The SRI indicated in slot n is associated with mostrecent transmission of the SRS resource identified by the SRI and here,the SRS transmission precedes PDCCH (i.e., slot n) carrying the SRI.

DMRS (Demodulation Reference Signal)

A DMRS related operation for PDSCH reception is described.

When a UE receives a PDSCH scheduled by DCI format 1_0 or receives aPDSCH before configuring an arbitrary dedicated higher layer amongdmrs-AdditionalPosition, maxLength and dmrs-Type parameters, the UEassumes that a PDSCH is not existed in an arbitrary symbol that carriesa DM-RS excluding a PDSCH having an allocation duration of two symbolshaving PDSCH mapping type B, a single symbol front-loaded DM-RS ofconfiguration type 1 is transmitted on DM-RS port 1000, and all ofremaining orthogonal antenna ports are not related to transmission ofPDSCH to another UE.

Additionally, for a PDSCH having mapping type A, the UE assumes thatdmrs-AdditionalPosition=‘pos2’ and a maximum of two additionalsingle-symbol DM-RSs are existed in a slot depending on a PDSCHduration. With respect to a PDSCH having an allocation duration of 7symbols for a normal CP or 6 symbols for an extended CP having mappingtype B, when front-loaded DM-RS symbols are located at the 1^(st) and2^(nd) symbols of PDSCH allocation duration, respectively, the UEassumes that an additional single symbol DM-RS is existed in the 5^(th)or 6^(th) symbol. Otherwise, the UE assumes that an additional DM-RSsymbol is not existed. In addition, with respect to a PDSCH having anallocation duration of 4 symbols having mapping type B, the UE assumesthat no more additional DM-RS symbol is not existed, with respect to aPDSCH having an allocation duration of 2 symbols having mapping type B,the UE assumes that an additional DM-RS symbol is not existed, and theUE assumes that a PDSCH is existed in a symbol that carries a DM-RS.

FIG. 9 is a flowchart illustrating an example of DL DMRS procedure.

A BS transmits DMRS configuration information to a UE (step S910).

The DMRS configuration information may refer to a DMRS-DownlinkConfiginformation element (IE). The DMRS-DownlinkConfig IE may include admrs-Type parameter, a dmrs-AdditionalPosition parameter, a maxLengthparameter, and a phaseTrackingRS parameter.

The ‘dmrs-Type’ parameter is a parameter for selecting a DMRSconfiguration type to be used for DL. In NR, the DMRS may be dividedinto two configuration types: (1) DMRS configuration type 1 and (2) DMRSconfiguration type 2. DMRS configuration type 1 has a higher RS densityin the frequency domain, and DMRS configuration type 2 has more DMRSantenna ports.

The ‘dmrs-AdditionalPosition’ parameter is a parameter indicating theposition of an additional DMRS on DL. In the case that the correspondingparameter is not existed, the UE applies pos2 value. For the DMRS, afirst position of front-loaded DMRS is determined according to PDSCHmapping type (type A or type B), and an additional DMRS may be set tosupport the UE of high speed. The front-loaded DMRS is indicated by RRCsignaling and DCI (downlink control information).

The ‘maxLength’ parameter is a parameter indicating the maximum numberof OFDM symbols for a DL front-loaded DMRS. The phaseTrackingRSparameter is a parameter for configuring a DL PTRS. In the case that theparameter is not existed or terminated, the UE assumes that there is noDL PTRS.

The BS generates a sequence used for DMRS (step S920).

The sequence for DMRS is generated according to Equation 3 below.

$\begin{matrix}{{r(n)} = {{\frac{1}{\sqrt{2}}( {1 - {2 \cdot {c( {2n} )}}} )} + {j\frac{1}{\sqrt{2}}( {1 - {2 \cdot {c( {{2n} + 1} )}}} )}}} & \lbrack {{Equation}\mspace{14mu} 3} \rbrack\end{matrix}$

The pseudo-random sequence c(i) is defined in 3gpp TS 38.211 5.2.1. Thatis, c(i) may be a gold sequence of length-31 using two m-sequences. Apseudo-random sequence generator is initialized by Equation 4 below.

c _(init)(2¹⁷(N _(symb) ^(slot) n _(s,f) ^(μ) +l+1)(2N _(ID) ^(n)^(SCID) +1)+2N _(ID) ^(n) ^(SCID) +n _(SCID))mod 2³¹  [Equation 4]

Here, l is the number of OFDM symbol in a slot, and n_(s,f) ^(μ) is aslot number in a frame.

Furthermore, if N_(ID) ⁰,N_(ID) ¹∈{0, 1, . . . , 65535} is provided, andin the case that a PDSCH is scheduled by a PDCCH using DCI format 1_1with CRC scrambled by C-RNTI, MCS-C-RNTI, or CS-RNTI, N_(ID) ⁰,N_(ID)¹∈{0, 1, . . . , 65535} is given by higher-layer parameter scramblingID0and scramblingID1 in DMRS-DownlinkConfig IE, respectively.

-   -   If N_(ID) ⁰∈{0, 1, . . . , 65535} is provided, and in the case        that a PDSCH is scheduled by a PDCCH using DCI format 1_0 with        CRC scrambled by C-RNTI, MCS-C-RNTI, or CS-RNTI, N_(ID) ⁰∈{0, 1,        . . . , 65535} is given by higher-layer parameter scramblingID0        in DMRS-DownlinkConfig IE.    -   N_(ID) ^(n) ^(SCID) =N_(ID) ^(cell), otherwise, and in the case        that DCI format 1_1 is used, quantity n_(SCID)∈{0, 1} is given        by a DMRS sequence initialization field in DCI which is        associated with PDSCH transmission.

The BS maps the generated sequence to a resource element (step S930).Here, the resource element may include at least one of a time, afrequency, an antenna port, or code.

The BS transmits the DMRS to the UE on the resource element (step S940).The UE receives a PDSCH using the received DMRS.

UE DM-RS Transmission Procedure

A DMRS related operation for PUSCH reception is described. As describedabove, UL means a signal transmission (or communication) from a UE to aBS. UL DMRS related operation may be similar to the DL DMRS relatedoperation described above, and the terms of the parameters related to DLmay be substituted by parameters related to UL.

That is, DMRS-DownlinkConfig IE may be substituted by DMRS-UplinkConfigIE, PDSCH mapping type may be substituted by PUSCH mapping type, andPDSCH may be substituted by PUSCH. Furthermore, in the DL DMRS relatedoperation, the BS may be substituted by the UE, and the UE may besubstituted by the BS. A sequence generation for UL DMRS may bedifferently defined depending on whether transform precoding is enabled.

Hereinafter, UE DM-RS transmission procedure is described in moredetail.

In the case that a transmitted PUSCH is not scheduled by DCI format 0_1with CRC scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI and does notcorrespond to a configured grant, the UE uses a single symbolfront-loaded DM-RS of configuration type 1 in DM-RS port 0, and theremaining RE not used for DM-RS in the symbols is not used for any PUSCHtransmission except the PUSCH having an allocation duration of an OFDMsymbol of 2 or less having disabled transform precoding. AdditionalDM-RS may be transmitted according to a scheduling type and a PUSCHduration by considering whether frequency hopping is enabled.

In the case that the frequency hopping is disabled, the UE assumes thatdmrs-AdditionalPosition may be the same as ‘pos2’, and a maximum of 2additional DM-RSs may be transmitted according to the PUSCH duration. Inthe case that the frequency hopping is enabled, the UE assumes thatdmrs-AdditionalPosition may be the same as ‘pos1’, and a maximum of oneadditional DM-RSs may be transmitted according to a PUSCH duration.

When a transmitted PUSCH is scheduled by activated DCI format 0_0 havingscrambled CRC by CS-RNTI, the UE uses a single symbol front-loaded DM-RSof a configuration type provided by higher layer parameter dmrs-Type ofconfiguredGrantConfig on DM-RS port 0, and the remaining RE not used forDM-RS in the symbols is not used for any PUSCH transmission except thePUSCH having an allocation duration of an OFDM symbol of 2 or lesshaving disabled transform precoding. Further, additional DM-RS withdmrs-AdditionalPosition from configuredGrantConfig may be transmittedbased on a scheduling type and a PUSCH duration by considering whetherfrequency hopping is enabled.

In the case that a transmitted PUSCH is scheduled by DCI format 0_1 withCRC scrambled by C-RNTI, CS-RNTI, or MCS-C-RNTI and corresponds to aconfigured grant,

-   -   The UE may be configured to higher layer parameter dmrs-Type in        DMRS-UplinkConfig, and the configured DM-RS configuration type        may be used for PUSCH transmission.    -   The UE may be configured with a maximum number of front-loaded        DM-RS symbols for PUSCH by higher layer parameter maxLength in        DMRS-UplinkConfig.

In the case that the UE that transmits a PUSCH is configured to higherlayer parameter phaseTrackingRS in DMRS-UplinkConfig, the UE may assumethat the following configurations may not coincide by the transmittedPUSCH.

-   -   With respect to DM-RS configuration type 1 and type 2, an        arbitrary DM-RS port among 4-7 or 6-11 is scheduled by each UE,        and a PT-RS is transmitted by the UE.

With respect to a PUSCH scheduled by DCI format 0_1, by activated DCIformat 0_1 with CRC scrambled by CS-RNTI or configured grant type 1, theUE assumes that DM-RS CDM group is not used for data transmission.

QCL (Quasi-Co Location)

The antenna port is defined so that a channel in which the symbol on theantenna port is transported may be inferred from a channel in whichdifferent symbols on the same antenna port are transported. When aproperty of a channel in which a symbol on one antenna port istransported may be interred from a channel in which symbols on differentantenna ports are transported, two antenna ports may have a quasico-located or quasi co-location (QC/QCL) relationship.

Here, the channel property includes at least one of a delay spread, aDoppler spread, a frequency/Doppler shift, average received power,received timing/average delay, and a spatial Rx parameter. Here, thespatial Rx parameter means a spatial (receive) channel propertyparameter such as angle of arrival.

The US may be configured as a list of up to M TCI-State configurationsin higher layer parameter PDSCH-Config in order to decode the PDSCHaccording to detected PDCCH having an intended DCI for the correspondingUE and a given serving cell. The M depends on a UE capability.

Each TCI-State includes a parameter for configuring a quasi co-locationrelationship between one or two DL reference signals and a DM-RS port ofthe PDSCH.

The quasi co-location relationship is configured as higher layerparameter qcl-Type1 for a first DL RS and qcl-Type2 (when configured)for a second DL RS. Two DL RSs are not the same as each other in termsof QCL type regardless of whether two DL RS are DL RSs having the samereference or DL RSs having different references.

A quasi co-location type corresponding to each DL RS may be given byhigher layer parameter qcl-Type of QCL-Info and may take one of thefollowing values:

-   -   ‘QCL-TypeA’: {Doppler shift, Doppler spread, average delay,        delay spread}    -   ‘QCL-TypeB’: {Doppler shift, Doppler spread}    -   ‘QCL-TypeC’: {Doppler shift, average delay}    -   ‘QCL-TypeD’: {Spatial Rx parameter}

For example, when a target antenna port is specific NZP CSI-RS,corresponding NZP CSI-RS antenna ports may be indicated/configured to beQCL with specific TRS from the viewpoint of QCL-Type A and specific SSBfrom the viewpoint of QCL-Type D. The UE that receives theindication/configuration may receive the corresponding NZP CSI-RS byusing a Doppler delay value measured in QCL-TypeATRS and apply an Rxbeam used for receiving QCL-TypeD SSB to reception of the correspondingNZP CSI-RS.

The UE may receive an activation command by MAC CE signaling which isused for mapping TCI states up to 8 to a codepoint DCI field‘Transmission Configuration Indication’.

With respect to a beam indication, the UE may be configured by RRC witha list for a maximum of M candidate Transmission ConfigurationIndication (TCI) states for the purpose of at least QCL (QuasiCo-location) indication. Here, M may be 64.

Each TCI state may be set to one RS set. Each ID of the DL RSs for aspatial QCL purpose (QCL type D) in at least RS set may be referred toone of DL RS types such as SSB, P-CSI RS, SP-CSI RS, A-CSI RS, and thelike. The initialization/update of the ID of the DL RS(s) in the RS setused for at least a spatial QCL purpose may be performed through atleast explicit signaling.

TCI-State IE is associated with quasi co-location (QCL) type thatcorresponds to one or two DL reference signal (RS). TCI-State IE mayinclude a parameter such as bwp-Id/referencesignal/QCL type, and thelike.

The bwp-Id parameter indicates a DL BWP on which the RS is located, thecell parameter indicates a carrier on which the RS is located, and thereferencesignal parameter indicates a reference antenna port(s) thatbecomes a source of quasi co-location for the corresponding targetantenna port(s) or a reference signal including the reference antennaport(s). The target antenna port(s) may be CSI-RS, PDCCH DMRS, or PDSCHDMRS. In one example, in order to indicate QCL reference RS informationfor NZP CSI-RS, the NZP CSI-RS resource configuration information mayindicate the corresponding TCI state ID. In another example, in order toindicate QCL reference information for PDCCH DMRS antenna port(s), eachCORESET configuration may indicate the TCI state ID. In still anotherexample, in order to indicate QCL reference information for PDSCH DMRSantenna port(s), TCI state ID may be indicated through DCI.

CSI Related Operation

In a New Radio (NR) system, a channel state information-reference signal(CSI-RS) is used for time and/or frequency tracking, CSI computation,layer 1 (L1)-reference signal received power (RSRP) computation, andmobility. Here, the CSI computation is related to CSI acquisition, andL1-RSRP computation is related to beam management (BM).

Channel state information (CSI) collectively refers to information thatmay indicate the quality of a radio channel (or referred to as a link)formed between the UE and the antenna port.

FIG. 10 is a flowchart illustrating an example of a CSI relatedprocedure.

Referring to FIG. 10, in order to perform one of usages of the CSI-RS, aterminal (e.g., user equipment (UE)) receives, from a base station(e.g., general Node B or gNB), configuration information related to theCSI through radio resource control (RRC) signaling (step S1010).

The configuration information related to the CSI may include at leastone of CSI-interference management (IM) resource related information,CSI measurement configuration related information, CSI resourceconfiguration related information, CSI-RS resource related information,or CSI report configuration related information.

The CSI-IM resource related information may include CSI-IM resourceinformation, CSI-IM resource set information, and the like. The CSI-IMresource set is identified by a CSI-IM resource set identifier (ID), andone resource set includes at least one CSI-IM resource. Each CSI-IMresource is identified by a CSI-IM resource ID.

The CSI resource configuration related information may be expressed asCSI-ResourceConfig IE. The CSI resource configuration relatedinformation defines a group including at least one of a non-zero power(NZP) CSI-RS resource set, a CSI-IM resource set, or a CSI-SSB resourceset. In other words, the CSI resource configuration related informationmay include a CSI-RS resource set list and the CSI-RS resource set listmay include at least one of a NZP CSI-RS resource set list, a CSI-IMresource set list, or a CSI-SSB resource set list. The CSI-RS resourceset is identified by a CSI-RS resource set ID, and one resource setincludes at least one CSI-RS resource. Each CSI-RS resource isidentified by a CSI-RS resource ID.

Table 5 represents an example of NZP CSI-RS resource set IE. Asrepresented in Table 5, parameters (e.g., a BM related ‘repetition’parameter and a tracking related ‘trs-Info’ parameter) representing theusage of CSI-RS may be configured for each NZP CSI-RS resource set.

TABLE 5  -- ASN1START  -- TAG-NZP-CSI-RS-RESOURCESET-START NZP-CSI-RS-ResourceSet ::= SEQUENCE {   nzp-CSI-ResourceSetId NZP-CSI-RS-ResourceSetId,   nzp-CSI-RS-Resources  SEQUENCE (SIZE(1..maxNrofNZP-CSI-RS- ResourcesPerSet)) OF NZP-CSI-RS-ResourceId,  repetition  ENUMERATED { on, off }   aperiodicTriggeringOffset INTEGER(0..4)   trs-Info  ENUMERATED {true}   ...  }  --TAG-NZP-CSI-RS-RESOURCESET-STOP  -- ASN1STOP

In addition, the repetition parameter corresponding to the higher layerparameter corresponds to ‘CSI-RS-ResourceRep’ of L1 parameter.

The CSI report configuration related information includes areportConfigType parameter representing a time domain behavior and areportQuantity parameter representing a CSI related quantity forreporting. The time domain behavior may be periodic, aperiodic, orsemi-persistent.

The CSI report configuration related information may be expressed asCSI-ReportConfig IE, and Table 6 below represents an example ofCSI-ReportConfig IE.

TABLE 6  -- ASN1START  -- TAG-CSI-RESOURCECONFIG-START  CSI-ReportConfig::= SEQUENCE {   reportConfigId  CSI-ReportConfigId,   carrier ServCellIndex OPTIONAL, - - Need S   resourcesForChannelMeasurement  CSI-ResourceConfigId,   csi-IM-ResourcesForInterference  CSI-ResourceConfigId OPTIONAL, - - Need R  nzp-CSI-RS-ResourcesForInterference   CSI-ResourceConfigIdOPTIONAL, - - Need R   reportConfigType  CHOICE {    periodic   SEQUENCE {     reportSlotConfig     CSI- ReportPeriodicityAndOffset,    pucch-CSI-ResourceList      SEQUENCE (SIZE (1..maxNrofBWPs)) OFPUCCH-CSI-Resource    },    semiPersistentOnPUCCH    SEQUENCE {    reportSlotConfig     CSI- ReportPeriodicityAndOffset,    pucch-CSI-ResourceList      SEQUENCE (SIZE (1..maxNrofBWPs)) OFPUCCH-CSI-Resource    },    semiPersistentOnPUSCH    SEQUENCE {    reportSlotConfig     ENUMERATED {sl5, sl10, sl20, sl40, sl80, sl160,sl320},     reportSlotOffsetList    SEQUENCE (SIZE (1.. maxNrofUL-Allocations)) OF INTEGER(0..32),     p0alpha     P0-PUSCH-AlphaSetId   },    aperiodic    SEQUENCE {     reportSlotOffsetList    SEQUENCE(SIZE (1..maxNrofUL- Allocations)) OF INTEGER(0..32)    }   },  reportQuantity  CHOICE {    none    NULL,    cri-RI-PMI-CQI    NULL,   cri-RI-i1    NULL,    cri-RI-i1-CQI    SEQUENCE {    pdsch-BundleSizeForCSI      ENUMERATED {n2, n4}  OPTIONAL    },   cri-RI-CQI    NULL,    cri-RSRP    NULL,    ssb-Index-RSRP    NULL,   cri-RI-LI-PMI-CQI    NULL   },

The UE measures CSI based on configuration information related to theCSI (step S1020). The CSI measurement may include (1) a CSI-RS receptionprocess of the UE (step S1021) and (2) a process of computing the CSIthrough the received CSI-RS (step S1022), and a detailed descriptionthereof will be described below.

For the CSI-RS, resource element (RE) mapping of a CSI-RS resource isconfigured time and frequency domains by higher layer parameterCSI-RS-ResourceMapping.

Table 7 represents an example of CSI-RS-ResourceMapping IE.

TABLE 7   -- ASN1START  -- TAG-CSI-RS-RESOURCEMAPPING-START CSI-RS-ResourceMapping ::= SEQUENCE {   frequencyDomainAllocation CHOICE {    row1    BIT STRING (SIZE (4)),    row2    BIT STRING (SIZE(12)),    row4    BIT STRING (SIZE (3)),    other    BIT STRING (SIZE(6))   },   nrofPorts  ENUMERATED {p1,p2,p4,p8,p12,p16,p24,p32},  firstOFDMSymbolInTimeDomain  INTEGER (0..13),  firstOFDMSymbolInTimeDomain2  INTEGER (2..12)   cdm-Type  ENUMERATED{noCDM, fd-CDM2, cdm4-FD2-TD2, cdm8- FD2-TD4},   density  CHOICE {   dot5    ENUMERATED {evenPRBs, oddPRBs},    one    NULL,    three   NULL,    spare    NULL   },   freqBand  CSI-FrequencyOccupation,  ...  }

In Table 7, a density (D) represents a density of the CSI-RS resourcemeasured in RE/port/physical resource block (PRB), and nrofPortsrepresents the number of antenna ports.

The UE reports the measured CSI to the BS (step S1030).

Here, in the case that a quantity of CSI-ReportConfig of Table 7 isconfigured to ‘none (or No report)’, the UE may skip the report.

However, even in the case that the quantity is configured to ‘none (orNo report)’, the UE may report the measured CSI to the BS.

The case where the quantity is configured to ‘none (or No report)’ is acase of triggering aperiodic TRS or a case where repetition isconfigured.

Here, only in the case where the repetition is configured to ‘ON’, thereport of the UE may be skipped.

CSI Measurement

The NR system supports more flexible and dynamic CSI measurement andreporting. Here, the CSI measurement may include a procedure ofacquiring the CSI by receiving the CSI-RS and computing the receivedCSI-RS.

As time domain behaviors of the CSI measurement and reporting,aperiodic/semi-persistent/periodic channel measurement (CM) andinterference measurement (IM) are supported. A 4 port NZP CSI-RS REpattern is used for configuring the CSI-IM.

CSI-IM based IMR of the NR has a similar design to the CSI-IM of the LTEand is configured independently of ZP CSI-RS resources for PDSCH ratematching. In addition, in NZP CSI-RS based IMR, each port emulates aninterference layer having (a preferable channel and) precoded NZPCSI-RS. This is for intra-cell interference measurement with respect toa multi-user case and primarily targets MU interference.

The BS transmits the precoded NZP CSI-RS to the UE on each port of theconfigured NZP CSI-RS based IMR.

The UE assumes a channel/interference layer for each port and measuresinterference.

In respect to the channel, when there is no PMI and RI feedback,multiple resources are configured in a set, and the BS or the networkindicates a subset of NZP CSI-RS resources through the DCI with respectto channel/interference measurement.

Resource setting and resource setting configuration will be described inmore detail.

Resource Setting

Each CSI resource setting ‘CSI-ResourceConfig’ includes a configurationfor S≥1 CSI resource set (given by higher layer parametercsi-RS-ResourceSetList). The CSI resource setting corresponds to theCSI-RS-resourcesetlist. Here, S represents the number of configuredCSI-RS resource sets. Here, the configuration for S≥1 CSI resource setincludes each CSI resource set including CSI-RS resources (constitutedby NZP CSI-RS or CSI IM) and an SS/PBCH block (SSB) resource used forL1-RSRP computation.

Each CSI resource setting is positioned in a DL BWP (bandwidth part)identified by a higher layer parameter bwp-id. In addition, all CSIresource settings linked to CSI reporting setting have the same DL BWP.

A time domain behavior of the CSI-RS resource within the CSI resourcesetting included in CSI-ResourceConfig IE is indicated by higher layerparameter resourceType and may be configured to be aperiodic, periodic,or semi-persistent. The number S of configured CSI-RS resource sets islimited to ‘1’ with respect to periodic and semi-persistent CSI resourcesettings. Periodicity and slot offset which are configured are given innumerology of associated DL BWP as given by bwp-id with respect to theperiodic and semi-persistent CSI resource settings.

When the UE is configured as multiple CSI-ResourceConfigs including thesame NZP CSI-RS resource ID, the same time domain behavior is configuredwith respect to CSI-ResourceConfig.

When the UE is configured as multiple CSI-ResourceConfigs including thesame CSI-IM resource ID, the same time domain behavior is configuredwith respect to CSI-ResourceConfig.

Next, one or more CSI resource settings for channel measurement (CM) andinterference measurement (IM) are configured through higher layersignaling.

-   -   CSI-IM resource for interference measurement.    -   NZP CSI-RS resource for interference measurement.    -   NZP CSI-RS resource for channel measurement.

That is, channel measurement resource (CMR) may be NZP CSI-RS andinterference measurement resource (IMR) may be NZP CSI-RS for CSI-IM andIM.

Here, CSI-IM (or ZP CSI-RS for IM) is primarily used for inter-cellinterference measurement.

In addition, NZP CSI-RS for IM is primarily used for intra-cellinterference measurement from multi-users.

The UE may assume CSI-RS resource(s) for channel measurement andCSI-IM/NZP CSI-RS resource(s) for interference measurement configuredfor one CSI reporting are ‘QCL-TypeD’ for each resource.

Resource Setting Configuration

As described, the resource setting may mean a resource set list.

In each trigger state configured by using higher layer parameterCSI-AperiodicTriggerState with respect to aperiodic CSI, eachCSI-ReportConfig is associated with one or multiple CSI-ReportConfigslinked to the periodic, semi-persistent, or aperiodic resource setting.

One reporting setting may be connected with a maximum of three resourcesettings.

-   -   When one resource setting is configured, the resource setting        (given by higher layer parameter resourcesForChannelMeasurement)        is used for channel measurement for L1-RSRP computation.    -   When two resource settings are configured, a first resource        setting (given by higher layer parameter        resourcesForChannelMeasurement) is used for channel measurement        and a second resource setting (given by        csi-IM-ResourcesForInterference or        nzp-CSI-RS-ResourcesForInterference) is used for interference        measurement performed on CSI-IM or NZP CSI-RS.    -   When three resource settings are configured, a first resource        setting (given by resourcesForChannelMeasurement) is for channel        measurement, a second resource setting (given by        csi-IM-ResourcesForInterference) is for CSI-IM based        interference measurement, and a third resource setting (given by        nzp-CSI-RS-ResourcesForInterference) is for NZP CSI-RS based        interference measurement.

Each CSI-ReportConfig is linked to periodic or semi-persistent resourcesetting with respect to semi-persistent or periodic CSI.

-   -   When one resource setting (given by        resourcesForChannelMeasurement) is configured, the resource        setting is used for channel measurement for L1-RSRP computation.    -   When two resource settings are configured, a first resource        setting (given by resourcesForChannelMeasurement) is used for        channel measurement and a second resource setting (given by        higher layer parameter csi-IM-ResourcesForInterference) is used        for interference measurement performed on CSI-IM.

CSI Computation

When interference measurement is performed on CSI-IM, each CSI-RSresource for channel measurement is associated with the CSI-IM resourcefor each resource by an order of CSI-RS resources and CSI-IM resourceswithin a corresponding resource set. The number of CSI-RS resources forchannel measurement is equal to the number of CSI-IM resources.

In addition, when the interference measurement is performed in the NZPCSI-RS, the UE does not expect to be configured as one or more NZPCSI-RS resources in the associated resource set within the resourcesetting for channel measurement.

A UE in which Higher layer parameter nzp-CSI-RS-ResourcesForInterferenceis configured does not expect that 18 or more NZP CSI-RS ports will beconfigured in the NZP CSI-RS resource set.

For CSI measurement, the UE assumes the followings.

-   -   Each NZP CSI-RS port configured for interference measurement        corresponds to an interference transport layer.    -   In all interference transport layers of the NZP CSI-RS port for        interference measurement, an energy per resource element (EPRE)        ratio is considered.    -   Different interference signals on RE(s) of the NZP CSI-RS        resource for channel measurement, the NZP CSI-RS resource for        interference measurement, or CSI-IM resource for interference        measurement.

CSI Reporting

For CSI reporting, time and frequency resources which may be used by theUE are controlled by the BS.

The channel state information (CSI) may include at least one of achannel quality indicator (CQI), a precoding matrix indicator (PMI), aCSI-RS resource indicator (CRI), an SS/PBCH block resource indicator(SSBRI), a layer indicator (LI), a rank indicator (RI), and L1-RSRP.

For the CQI, PMI, CRI, SSBRI, LI, RI, and L1-RSRP, the UE is configuredby a higher layer as N≥1 CSI-ReportConfig reporting setting, M≥1CSI-ResourceConfig resource setting, and a list (provided byaperiodicTriggerStateList and semiPersistentOnPUSCH) of one or twotrigger states. In the aperiodicTriggerStateList, each trigger stateincludes the channel and an associated CSI-ReportConfigs list optionallyindicating resource set IDs for interference. In thesemiPersistentOnPUSCH-TriggerStateList, each trigger state includes oneassociated CSI-ReportConfig.

In addition, the time domain behavior of CSI reporting supportsperiodic, semi-persistent, and aperiodic.

i) The periodic CSI reporting is performed on short PUCCH and longPUCCH. The periodicity and slot offset of the periodic CSI reporting maybe configured as RRC and refer to the CSI-ReportConfig IE.

ii) Semi-periodic (SP) CSI reporting is performed on short PUCCH, longPUCCH, or PUSCH.

In the case of SP CSI on the short/long PUCCH, the periodicity and theslot offset are configured as the RRC and the CSI reporting to separateMAC CE/DCI is activated/deactivated.

In the case of the SP CSI on the PUSCH, the periodicity of the SP CSIreporting is configured through the RRC, but the slot offset is notconfigured through the RRC, and the SP CSI reporting isactivated/deactivated by DCI (format 0_1). Separated RNTI (SP-CSIC-RNTI) is used with respect to the SP CSI reporting on the PUSCH.

An initial CSI reporting timing follows a PUSCH time domain allocationvalue indicated in the DCI and a subsequent CSI reporting timing followsa periodicity configured through the RRC.

DCI format 0_1 may include a CSI request field and mayactivate/deactivate a specific configured SP-CSI trigger state. The SPCSI reporting has the same or similar activation/deactivation as amechanism having data transmission on SPS PUSCH.

iii) The aperiodic CSI reporting is performed on the PUSCH and istriggered by the DCI. In this case, information related to trigger ofaperiodic CSI reporting may be transferred/indicated/configured throughMAC-CE.

In the case of AP CSI having AP CSI-RS, an AP CSI-RS timing isconfigured by the RRC and a timing for AP CSI reporting is dynamicallycontrolled by the DCI.

The NR does not adopt a scheme (for example, transmitting RI, WBPMI/CQI, and SB PMI/CQI in order) of dividing and reporting the CSI inmultiple reporting instances applied to PUCCH based CSI reporting in theLTE. Instead, the NR restricts specific CSI reporting not to beconfigured in the short/long PUCCH and a CSI omission rule is defined.In addition, in relation with the AP CSI reporting timing, a PUSCHsymbol/slot location is dynamically indicated by the DCI. In addition,candidate slot offsets are configured by the RRC. For the CSI reporting,slot offset(Y) is configured for each reporting setting. For UL-SCH,slot offset K2 is configured separately.

Two CSI latency classes (low latency class and high latency class) aredefined in terms of CSI computation complexity. The low latency CSI is aWB CSI that includes up to 4 ports Type-I codebook or up to 4-portsnon-PMI feedback CSI. The high latency CSI refers to CSI other than thelow latency CSI. For a normal UE, (Z, Z′) is defined in a unit of OFDMsymbols. Here, Z represents a minimum CSI processing time from thereception of the aperiodic CSI triggering DCI to the execution of theCSI reporting. Further, Z′ represents a minimum CSI processing time fromthe reception of the CSI-RS for channel/interference to the execution ofthe CSI reporting.

Additionally, the UE reports the number of CSIs which may besimultaneously calculated.

The descriptions (e.g., 3GPP system, frame structure, DL and ULtransmission/reception operation, etc.) described above may beapplied/used in combination with the method and/or embodiments proposedin the present disclosure or supplemented to clarify the technicalfeature of the methods proposed in the present disclosure. In thepresent disclosure, the sign “/” may mean that all or some of thecontents distinguished by “/” are included.

Multi-TRP (Transmission/Reception Point)

According to the Coordinated Multi Point (CoMP) technique, multiple BSsexchange (e.g., using X2 interface) or utilize channel information(e.g., RI/CQI/PMI/LI, etc.) feedbacked from UEs and perform cooperativetransmission with UEs, and thereby controlling interference efficiently.The CoMP technique may be distinguished into Joint transmission (JT),Coordinated scheduling (CS), Coordinated beamforming (CB), DPS (dynamicpoint selection), DPB (dynamic point blacking), and the like accordingto the scheme to be used.

NCJT (Non-coherent joint transmission) may mean cooperative transmissionnot considering interference (i.e., without interference). For example,the NCJT may be a technique for a BS(s) to transmit data using the sametime resource and frequency resource to a single UE through multipleTRPs. According to the technique, the multiple TRPs of the BS(s) may beconfigured to transmit data to the UE using different DMRS (demodulationreference signal) ports with each other through different layers. Inother words, the NCJT may correspond to a transmission technique inwhich transmission of MIMO layer(s) is performed from two or more TRPswithout adaptive precoding among TRPs.

The NCJT may be classified into fully overlapped NCJT scheme in whichtime resources and frequency resources used by each BS (or TRP) fortransmission are fully overlapped and partially overlapped NCJT in whichtime resources and/or frequency resources used by each BS (or TRP) fortransmission are partially overlapped. This is just for the convenienceof description in the present disclosure, and the terms described abovemay be substituted by different term having the same technical meaningin the embodiments and methods to be described below. For example, inthe case of the partially overlapped NCJT, in a part of time resourcesand/or frequency resources, all of data of a first BS (e.g., TRP 1) anddata of a second BS (e.g., TRP 2) may be transmitted, and in theremaining time resources and/or frequency resources, data of either oneof the first BS or the second BS may be transmitted.

The TRP forwards data scheduling information to the UE that receivesNCJT using DCI (Downlink Control Information). In the aspect of DCI(Downlink Control Information) transmission, M-TRP (multiple TRP)transmission scheme may be classified into i) M-DCI (multiple DCI) basedM-TRP transmission scheme in which each TRP transmits different DCI andii) S-DCI (single DCI) based M-TRP transmission scheme in which a singleTRP transmits DCI.

First, the single DCI based M-TRP transmission scheme is described. Inthe single DCI based M-TRP transmission scheme in which a representativeTRP forwards scheduling information for data transmitted by therepresentative TRP itself and data transmitted by another TRP withsingle DCI, the MTRP performs cooperative transmission together with acommon PDSCH, and each TRP participating in the cooperative transmissiondivides the corresponding PDSCH spatially with different layers (i.e.,different DMRS ports) and transmits the divided PDSCH. In other words,the MTRP transmits a single PDSCH, but each TRP transmits a part oflayer of multiple layers configuring a single PDSCH. For example, in thecase that 4-layer data is transmitted, TRP 1 transmits 2 layers, and TRP2 transmits the remaining 2 layers to the UE.

In this case, the scheduling information for the PDSCH is indicated tothe UE through single DCI, and the DCI indicates that a certain QCL RSand QCL type information is used by a DMRS port (this is different fromthe previous scheme: QCL RS and TYPE to be commonly applied to all DMRSports are indicated in DCI). That is, M TCI states are indicated throughthe TCI field in DCI (M=2, for 2 TRP cooperative transmission), and theQCL RS and type are identified by using different M TCI states for eachof M DMRS port groups. Furthermore, DMRS port information may beindicated by using a new DMRS table.

In one example, for S-DCI, since all types of scheduling information fordata transmitted by the MTRP is forwarded through single DCI, the S-DCImay be used in an ideal BH (ideal BackHaul) environment in which dynamiccooperation is possible between two TRPs.

Second, multiple-DCI based MTRP scheme is described. The MTRP transmitsdifferent DCI and a PDSCH (a UE receives N DCI and N PDSCHs from NTRPs), and the PDSCHs are transmitted in (partially or wholly)overlapping on a frequency-time resource. The PDSCH may be scramblingthrough different scrambling ID, and the DCI may be transmitted throughCoreset belonging to different Coreset group groups (the Coreset groupis identified by an index defined in Coreset configuration, e.g., whenindex=0 is configured for Coresets 1 and 2, and index=1 is configuredfor Coresets 3 and 4, Coresets 1 and 2 belong to Coreset group 0, andCoresets 3 and 4 belong to Coreset group. Further, in the case that anindex is not defined in a Coreset, it is interpreted that index=0). Inthe case that a plurality of scrambling IDs is configured in one servingcell or two or more Coreset groups are configured, the UE may receivedata in the multiple-DCI based MTRP operation.

In one example, whether the single-DCI based MTRP scheme or themultiple-DCI based MTRP scheme is applied may be indicated throughseparate signaling to the UE. For example, in the case that a pluralityCRS patterns is indicated to the UE for MTRP operation for a singleserving cell, PDSCH rate matching for CRS may be changed depending onwhether the single-DCI based MTRP scheme or the multiple-DCI based MTRPscheme is applied.

The BS described in the present disclosure may collectively mean anobject that performs data transmission/reception with the UE. Forexample, the BS described in the present disclosure may include one ormore TPs (Transmission Points), one or more TRPs (Transmission andReception Points), and the like. For example, the multiple TPs and/ormultiple TRPs described in the present disclosure may be included in asingle BS or multiple BSs. Furthermore, the TP and/or TRP may include apanel, a transmission and reception unit, and the like of the BS.

Furthermore, the TRP described in the present disclosure may mean anantenna array having one or more antenna elements available in a networklocated in a specific geographical location of a specific area. Thepresent disclosure is described based on “TRP” for the convenience ofdescription, but it is understood/applied that the TRP may besubstituted by a BS, a TP (transmission point), a cell (e.g., macrocell/small cell/pico cell, etc.), an antenna array, or a panel.

Furthermore, the CORESET group ID described in the present disclosuremay mean index/identification information (e.g., ID)/indicator fordistinguishing CORESET configured/associated (or for each TRP/panel) foreach TRP/panel. In addition, the CORESET group may be a group/union ofCORESET distinguished by index/identification information (e.g., ID)/theCORESET group ID to distinguish CORESET. For example, the CORESET groupID may be specific index information defined in a CORSET configuration.For example, the CORESET group may be configured/indicated/defined by anindex defined in the CORESET configuration for each CORESET. The CORESETgroup ID may be configured/indicated through higher layer signaling(e.g., RRC signaling)/L2 signaling (e.g., MAC-CE)/L1 signaling (e.g.,DCI).

M-TRP Transmission Technique

The M-TRP transmission technique for which a plurality of (e.g., M) TRPstransmits data to a single User Equipment (UE) may be classified intotwo types: eMBB M-TRP (or M-TRP eMMB) transmission, which is a schemefor increasing transmission rate significantly, and URLLC M-TRP (orM-TRP URLLC) transmission, which is a scheme for increasing receptionsuccess rate and decreasing latency.

The URLLC M-TRP may mean a scheme that an M-TRP transmits the same TB(Transport Block) using different resource (e.g., layer/timeresource/frequency resource, etc.). The UE configured with the URLLCM-TRP transmission scheme may indicated with several TCI states usingDCI and assume that data received using a QCL RS (reference signal) ofeach TCI state is the same TB. On the other hand, the eMBB M-TRP maymean a scheme that an M-TRP transmits different TB using differentresource (e.g., layer/time resource/frequency resource, etc.). The UEconfigured with the eMBB M-TRP transmission scheme may indicated withseveral TCI states using DCI and assume that data received using a QCLRS (reference signal) of each TCI state is different TB.

For example, the UE may distinguish and use an RNTI configured forMTRP-URLLC and an RNTI configured for MTRP-eMBB separately and maydetermine/decide whether the corresponding M-TRP transmission is URLLCtransmission or eMBB transmission. That is, in the case that CRC maskingof DCI received by the UE is performed by using the RNTI configured withMTRP-URLLC usage, this may correspond to URLLC transmission, and in thecase that CRC masking of DCI is performed by using the RNTI configuredwith MTRP-URLLC usage, this may correspond to eMBB transmission.

Table 8 represents various schemes which may be considered for URLLCM-TRP transmission. Referring to Table 8, various schemes of SDM/FDM/TDMschemes are existed.

TABLE 8 To facilitate further down-selection for one or more schemes inRANI#96bis, schemes for multi- TRP based URLLC, scheduled by single DCIat least, are clarified as following:  •  Scheme I (SDM): n (n <= N_(s))TCI states within the single slot, with overlapped time and  frequencyresource allocation  ▪ Scheme 1a:  •  Each transmission occasion is alayer or a set of layers of the same TB, with each layer or layer  setis associated with one TCI and one set of DMRS port(s).  •  Singlecodeword with one RV is used across all spatial layers or layer sets.From the UE  perspective, different coded bits are mapped to differentlayers or layer sets with the same  mapping rule as in Rel-15.  ▪ Scheme1b:  •  Each transmission occasion is a layer or a set of layers of thesame TB, with each layer or layer  set is associated with one TCI andone set of DMRS port(s).  •  Single codeword with one RV is used foreach spatial layer or layer set. The RVs corresponding  to each spatiallayer or layer set can be the same or different.  ▪ Scheme 1c:  •  Onetransmission occasion is one layer of the same TB with one DMRS portassociated with  multiple TCI state indices, or one layer of the same TBwith multiple DMRS ports associated  with multiple TCI state indices oneby one.  ▪ For Scheme 1a and 1c, the same MCS is applied for all layersor layer sets.  ▪ For scheme 1b, same or different MCS/modulation ordersfor different layers or layer sets can be  discussed.  •  Scheme 2(FDM): n (n <= N_(f)) TCI states within the single slot, withnon-overlapped frequency  resource allocation  ▪ Each non-overlappedfrequency resource allocation is associated with one TCI state.  ▪ Samesingle/multiple DMRS port(s) arc associated with all non-overlappedfrequency resource  allocations.  ▪ Scheme 2a:  •  Single codeword withone RV is used across full resource allocation. From UE perspective, the common RB mapping (codeword to layer mapping) is applied across fullresource allocation.  ▪ Scheme 2b:  •  Single codeword with one RV isused for each non-overlapped frequency resource allocation.  The RVscorresponding to each non-overlapped frequency resource allocation canbe the same or  different.  ▪ For scheme 2a, same MCS is applied for allnon-overlapped frequency resource allocations  ▪ For scheme 2b, same ordifferent MCS/modulation orders for different non-overlapped frequency resource allocations can be discussed.  ▪ Details of frequency resourceallocation mechanism for FDM 2a/2b with regarding to allocation granularity, time domain allocation can be discussed. • Scheme 3 (TDM):n (n <= N_(t1)) TCI states within the single slot, with non-overlappedtime resource allocation  ∘ Each transmission occasion of the TB has oneTCI and one RV with the time granularity of mini-slot.  ∘ Alltransmission occasion (s) within the slot use a common MCS with samesingle or multiple DMRS port(s).  ∘ RV/TCI state can be same ordifferent among transmission occasions.  ∘ FFS channel estimationinterpolation across mini-slots with the same TCI index • Scheme 4(TDM): n (n <= N_(t2)) TCI states with K (n <= K) different slots.  ∘Each transmission occasion of the TB has one TCI and one RV.  ∘ Alltransmission occasion (s) across K slots use a common MCS with samesingle or multiple DMRS port(s)  ∘ RV/TCI state can be same or differentamong transmission occasions.  ∘ FFS channel estimation interpolationacross slots with the same TCI index Note that M-TRP/panel based URLLCschemes shall be compared in terms of improved reliability, efficiency,and specification impact. Note: Support of number of layers per TRP maybe discussed

Reliability Improvement Method in Multi-TRP

FIG. 11 illustrates a transmission and reception method for reliabilityimprovement supported by multiple TRPs, and the following two methodsmay be considered.

The example of FIG. 11 (a) shows the case that a layer grouptransmitting the same CW (codeword)/TB (transport block) corresponds todifferent TRPs. That is, the same CW may be transmitted throughdifferent layer/layer group. In this case, a layer group may mean a kindof layer set including one or more layers. As such, amount of transportresource increases as the number of layer increases, and through this,there is an advantage that robust channel coding of low coding rate maybe used for a TB. In addition, since channels from multiple TRPs aredifferent, reliability improvement of a reception signal may be expectedbased on diversity gain.

Meanwhile, the example of FIG. 11 (b) shows the case that different CWsare transmitted through a layer group corresponding to different TRPs.That is, different CW may be transmitted through different layer/layergroup. In this case, it may be assumed that TBs corresponding to a firstCW (CW #1) and a second CW (CW #2) are the same. Accordingly, this maybe regarded as an example of a repeated transmission of the same TB. Inthe case of FIG. 11 (b), there is a disadvantage that coding ratecorresponding to a TB may be higher than that of FIG. 11 (a) case.However, there is an advantage that coding rate may be adjusted byindicating different RV (redundancy version) values for encoding bitsgenerated from the same TB depending on a channel environment, or amodulation order of each CW may be adjusted.

In FIG. 11 (a) or FIG. 11 (b), the same TB is repeatedly transmittedthrough different layer group and each layer group is transmitted bydifferent TRP/panel, and data reception probability may be increased,which is referred to as URLLC M-TRP transmission scheme based on SDM(spatial division multiplexing). Layer(s) belonged to different layergroup is respectively transmitted through DMRS ports belonged todifferent DMRS CDM groups.

Furthermore, the contents related to multiple TRPs described above maybe extendedly applied to FDM (frequency division multiplexing) schemebased on different frequency domain resource (e.g., RB/PRB (set)) and/orTDM (time division multiplexing) scheme based on different time domainresource (e.g., slot, symbol, or sub-symbol) as well as the SDM (spatialdivision multiplexing) scheme that uses different layers.

Hereinafter, in the present disclosure, when cooperative transmissionbetween multiple BSs (e.g., multiple TPs/TRPs of one or more BSs, etc.)and a UE (e.g., NCJT) is considered in a wireless communication system,the methods which may be proposed in the situation are described.Particularly, Proposal 1 proposes a method for configuring/defining aDMRS table which may be referenced in the case that multiple TCI statesare indicated to a UE in URLLC transmission based on MTRP. Proposal 2may define a new mapping rule such that all DMRS ports indicated to a UEmay correspond to the same TCI state in the case that MTRP-URLLCoperation is configured to a UE. Proposal 3 describes a method/rule fordefining a mapping relation between TCI state and CDM group (/DMRSport). Proposal 4 proposes a method for indicating/configuring that asingle user (SU) dedicated DMRS port combination may be used formultiple user (MU) usage. Proposal 5 proposes a method for determiningthe number of PTRS ports considering the case that multiple-TRP/paneltransmission is performed.

The methods described in the present disclosure is described based onone or more TPs/TRPs of a BS(s), but it is understood that the methodmay also be applied to transmission based on one or more panels of aBS(s) in the same or similar manner.

<Proposal 1>

For URLLC operation, in the case that a UE is configured through higherlayer signaling or succeeds in PDCCH decoding using a specific RNTIvalue, the UE may identify that the URLLC operation isconfigured/performed. Here, the URLLC operation means the MTRP-URLLCoperation performed by M-TRPs described above. In the case that theURLLC operation is configured, the UE may be defined/configured to referthe same DMRS table as the DMRS table referred in the case that singleTCI state is indicated even in the case that multiple TCI states areindicated in a TCI state field in DCI.

In the present disclosure, the TCI state field in DCI means‘Transmission configuration indication (TCI)’ field. In addition, thefact that multiple TCI states are indicated in a TCI state field in DCImay be interpreted that a code point of ‘Transmission configurationindication (TCI)’ field in DCI indicates multiple TCI states or may bemapped/corresponded to multiple TCI states.

As an example of higher layer configuration of URLLC operation, a methodof using higher layer parameter ‘pdsch-AggregationFactor’ may beconsidered. In Rel-15, ‘pdsch-AggregationFactor’ is a higher layerparameter indicating the number of repetitions for data, and a repeatedtransmission of the same TB (transport block) through a consecutive slotcorresponding to ‘pdsch-AggregationFactor’ may be configured to the UE.The parameter may be used for a parameter for indicating multiple TRPbased URLLC operation in Rel-16.

As an example of the specific RNTI value for configuring URLLCoperation, MCS (Modulation and Coding Scheme)-C-RNTI may be exemplified.MCS-C-RNTI may be used for the usage of indicating the UE to refer aspecific MCS index table (e.g., 3gpp TS 38.214 Table 5.1.3.1-3). Forexample, when receiving a PDSCH scheduled by a PDCCH including CRCscrambled with MCS-C-RNTI, the UE may determine a modulation order and atarget code rate used for a PDSCH based on the specific MCS index table.The MCS table is characterized to be configured with an MCS combinationin which relatively conservative transmission is available. Theconservative transmission may mean the case that stable datatransmission is available for the UE with low error rate even in thecase of low SNR since a coding rate of channel coding is low or amodulation order is low. Accordingly, the MCS-C-RNTI value may be usedfor the purpose of reliability improvement and utilized for the usage ofindicating URLLC operation to the UE.

The examples of configuring URLLC using higher layer configuration orspecific RNTI are just examples for the convenience of description, andnot intended to limit the technical scope of the present disclosure.Accordingly, other higher layer parameter or RNTI may be used for theURLLC operation configuration. In the case that the UE is configuredthrough higher layer parameter (e.g., pdsch-AggregationFactor) orsucceeds in PDCCH decoding using a specific RNTI value (e.g.,MCS-C-RNTI), the UE may identify that data is transmitted based on oneof the MTRP based URLLC operation schemes (e.g., SDM, FDM, or CDM, etc.)described in Table 8.

Together with the indication of URLLC operation to the UE based on ahigher layer configuration or a specific RNTI, a TCI state field in DCImay be used to indicate TCI state(s) corresponding to multiple TRPs tothe UE. Particularly, a specific code point of the TCI state field maycorrespond to/be mapped to multiple TCI states. In one example, in thecase that a TCI state field of DCI configured with 3 bits is assumed,the first code point ‘000’ may correspond to/be mapped to {TCI state A,TCI state B} configured with two TCI states.

As described above, in the case that URLLC operation isconfigured/indicated to the UE and multiple TCI states is indicatedthrough a specific code point of a TCI state field of DCI, the UE mayrefer the same DMRS table as the DMRS table referred in the case that asingle TCI state is indicated. For example, the DMRS table referable bythe UE in the case that a single TCI state is indicated may be the DMRStable defined in Rel-15 NR standard (e.g., 3gpp TS38.212 Table7.3.1.2.2-1/2/3/4, etc.).

Table 9 is an example of the DMRS table referable by the UE in the casethat a single TCI state is indicated and represents 3gpp TS38.212 Table7.3.1.2.2-1 standard. Table 9 is an example of the case that antennaport(s) (1000+DMRS port), dmrs-type=1, and maxlength=1.

TABLE 9 One Codeword: Codeword 0 enabled, Codeword 1 disabled Number ofDMRS CDM group(s) DMRS Value without data port(s) 0 1 0 1 1 1 2 1 0, 1 32 0 4 2 1 5 2 2 6 2 3 7 2 0, 1 8 2 2, 3 9 2 0-2 10  2 0-3 11  2 0, 212-15 Reserved Reserved

In the case of operating in the scheme above, there is an advantagebelow.

In the case that multiple TCI states are indicated through a specificcode point of a TCI state field in DCI, a DMRS table may be defined,which may be optimized for NCJT transmission for eMBB may be defined.

In the case that multiple TCI states are indicated through a specificcode point to the UE in Rel-16, a new DMRS table, which is differentfrom the DMRS table defined in Rel-15, may be defined. However, in thecase that URLLC transmission based on multiple TRPs is going to besupported, the DMRS table defined in Rel-15 is referred, and a DMRS portcombination for NCJT transmission for eMBB may be defined with moreoptimized in detail.

As another method, the UE configured with a higher layer configurationfor URLLC operation or succeeding in PDCCH decoding through a specificRNTI value may be defined/configured to refer a DMRS table configuredwith a subset of a DMRS port combination defined in Rel-15 DMRS table,in the case that multiple TCI states are indicated in a TCI state fieldin DCI.

Since high reliability is required for the UE operating in URLLC, it ishighly probable that the number of transmission layers is limited. Inthis case, a DMRS port combination for the number of layers that exceedsa specific number of layers among the DMRS port combination defined inRel-15 DMRS table may not be used. The specific number of layers may beconfigured to the UE by the BS through a higher layer configuration ordefined as a promised value between the BS and the UE in advance. In thecase that the DMRS port combination for the number of layers thatexceeds a specific number of layers is not used, a new DMRS table may beconfigured with a subset form (e.g., a part of state/row/column/entry,etc. among the predefined DMRS table) including layers of the number ofspecific layers or smaller in Rel-15 DMRS table (e.g., 3gpp TS38.212Table 7.3.1.2.2-1/2/3/4).

Table 10 represents an example of a DMRS table which may be applied tothe case that the UE is configured such that the DMRS port combinationfor the number of layers that exceeds 2 layers is not used. Table 10 isjust an example for the convenience of description but not intended tolimit the technical scope of the present disclosure.

TABLE 10 One Codeword: Two Codewords: Codeword 0 enabled, Codeword 0enabled, Codeword 1 disabled Codeword 1 enabled Number of Number of DMRSCDM Number of DMRS CDM Number of group(s) front- group(s) front- withoutDMRS load without DMRS load Value data port(s) symbols Value dataport(s) symbols 0 1 0 1 0-15 reserved reserved reserved 1 1 1 1 2 1 0, 11 3 2 0 1 4 2 1 1 5 2 2 1 6 2 3 1 7 2 0, 1 1 8 2 2, 3 1 9 2 0, 2 1 10 20 2 11 2 1 2 12 2 2 2 13 2 3 2 14 2 0, 4 2 15 2 2, 6 2

Table 10 represents an example configured with a subset form of Table7.3.1.2.2-2 of 3gpp TS38.212. In the conventional DMRS table, 0 to 31values are present, and 5 bits are required to indicate the values. InTable 10, a subset is configured with a DMRS port combinationcorresponding to a part of values of the conventional DMRS table and 0to 15 values are present, and 4 bits may be required to indicate thevalues.

In the example of Table 10, considering multiple user (MU) pairing, thenumber of total transmission layers does not exceed 4 in the aspect ofBS. This has a disadvantage that a part of DMRS port combination isunusable in the case that the number of front-load symbols is 2.However, in the URLLC aspect, since reliability improvement of aspecific UE is important, 2-symbol front-load DMRS may be used for thepurpose of channel estimation performance improvement, and a part ofcombination may be excluded. In the case of 2-symbol front-load DMRS,the reception power of DMRS may be improved. Particularly, in the caseof the combination in which values of the table correspond to 14 and 15,since the UE may not expect CDM in frequency domain, there is anadvantage that channel estimation performance may be improved in achannel environment in which frequency selectivity property is great.

As such, in the case that a new DMRS table of subset form is defined, abit number of a DCI field required for DMRS port indication may bedecreased, and the decreased bit may be used for other purpose. Forexample, when URLLC operation may operate based on FDM and/or TDM, thedecreased bit may be used for the purpose of selecting URLLC operationbased on FDM and/or TDM.

As a similar method to the proposal, in the case that the UE isconfigured through higher layer for URLLC operation and/or the UE thatsucceeds in PDCCH decoding using a specific RNTI value is indicated withmultiple TCI states in a TCI state field in DCI, the UE may not expectan indication for a specific state in the Rel-15 DMRS table. That is,the UE may not expect an indication for a state that corresponds to thenumber of layers that exceeds a specific number of layers. In this case,the specific number of layers may be configured to the UE by the BSthrough a higher layer configuration or defined as a promised valuebetween the BS and the UE in advance. In addition, the specific numberof layers may be differently defined/configured depending on a DMRStable configured to the UE (e.g., 3gpp TS38.212 Table 7.3.1.2.2-1/2/3/4,etc.).

<Proposal 2>

For URLLC operation, in the case that a UE is configured through higherlayer signaling or succeeds in PDCCH decoding using a specific RNTIvalue, the UE may identify that the URLLC operation isconfigured/performed. Here, the URLLC operation means the MTRP-URLLCoperation performed by M-TRPs described above. In the case that theURLLC operation is configured and in the case that multiple TCI statesare indicated in a TCI state field in DCI to the UE, each state maycorrespond to a specific time/frequency resource, and in this case, allDMRS ports indicated to the UE may correspond to the same TCI states.The time/frequency resource in Proposal 2 of the present disclosure maybe interpreted as a time resource, a frequency resource, or a time andfrequency resource.

In Rel-16, for at least eMBB, TCI indication framework needs to beimproved. Each TCI code point in DCI may correspond to 1 or 2 TCIstates. When 2 TCI states are activated within a TCI code point, eachTCI state corresponds to one CDM group, at least for DMRS type 1.

In other words, in the case that two TCI states are indicated, each TCIstate corresponds to a specific CDM group. That is, different TCI statesmay correspond to DMRS port groups of different CDM groups. This isintroduced for the purpose of minimizing mutual interference in channelestimation in the case that different TRPs transmit data throughoverlapped time/frequency resource domain, when eMBB transmission isassumed. That is, the situation in which different TRPs use overlappedtime/frequency resource domain is assumed.

However, in the case that multiple TRP-based URLLC operation isperformed, different TRPs transmit data through different (i.e., notoverlapped) time/frequency resource domains. In addition, the TRP thattransmits data using a specific time/frequency resource domain maytransmit data using all indicated DMRS ports. In this case, a specificTCI state needs to be corresponded in a specific time/frequency resourcedomain units, and all DMRS ports indicated to the UE need to correspondto the same TCI state. Accordingly, in the case that URLLC operation isconfigured/indicated to the UE, the conventional eMBB case is notfollowed, but a new rule needs to be defined such that all DMRS portsindicated to the UE correspond to the same TCI state.

<Proposal 3>

Table 11 and Table 12 represent examples of parameters for each PDSCHDMRS configuration type of 3gpp TS38.211 7.4.1.1 standard. Table 11represents parameters for PDSCH DMRS configuration type 1, and Table 12represents parameters for PDSCH DMRS configuration type 2. The value pin Table 11 and Table 12 is equal to the DMRS port value plus 1000.Through the contents described in Table 11 and Table 12, andDemodulation reference signals for PDSCH of 3gpp TS38.211 7.4.1.1standard, a correspondence relation between a DMRS port and a CDM groupmay be identified.

TABLE 11 CDM group w_(f)(k′) w_(t)(l′) p λ Δ k′ = 0 k′ = 1 l′ = 0 l′ = 11000 0 0 +1 +1 +1 +1 1001 0 0 +1 −1 +1 +1 1002 1 1 +1 +1 +1 +1 1003 1 1+1 −1 +1 +1 1004 0 0 +1 +1 +1 −1 1005 0 0 +1 −1 +1 −1 1006 1 1 +1 +1 +1−1 1007 1 1 +1 −1 +1 −1

TABLE 12 CDM group w_(f)(k′) w_(t)(l′) p λ Δ k′ = 0 k′ = 1 l′ = 0 l′ = 11000 0 0 +1 +1 +1 +1 1001 0 0 +1 −1 +1 +1 1002 1 2 +1 +1 +1 +1 1003 1 2+1 −1 +1 +1 1004 2 4 +1 +1 +1 +1 1005 2 4 +1 −1 +1 +1 1006 0 0 +1 +1 +1−1 1007 0 0 +1 −1 +1 −1 1008 1 2 +1 +1 +1 −1 1009 1 2 +1 −1 +1 −1 1010 24 +1 +1 +1 −1 1011 2 4 +1 −1 +1 −1

In addition, based on a value of antenna port(s) field indicated throughDCI in 3gpp TS38.212 7.3.1.2.2. Format1_1, the number of DMRS CDM groupsand the configuration of DMRS port may be identified. For example,through the antenna port(s) field of DCI, the state/value defined inTables 7.3.1.2.2-1/2/3/4 may be indicated, and ‘the number of CDM groupswithout data’ values, 1, 2, and 3 in the table (e.g., 3gpp TS38.212Tables 7.3.1.2.2-1/2/3/4) may mean CDM group {0}, {0,1}, and {0,1,2},respectively. Antenna ports {p0, . . . , pv−1} may be determinedaccording to an order of DMRS port(s) given by the table (e.g., 3gppTS38.212 Tables 7.3.1.2.2-1/2/3/4).

Furthermore, the UE may assume that (based on QCL assumption), differentTRPs correspond to different CDM groups. Accordingly, when the UEreceives PDSCH(s) from an M-TRP, the UE may distinguish each TRP througha CDM group and may perform the multiple-TRP related operation (e.g.,MTRP-URLLC related operation in Table 8) described above.

Hereinafter, in the case that multiple TCI states are indicated in a TCIstate field in DCI to the UE, a method/rule for defining a mappingrelation between each TCI state and CDM group (/DMRS port) is described.

Alt 1: A TCI state indicated to the UE may be orderly and sequentiallymapped to a CDM group. For example, a rule may be defined between the BSand the UE such that the first TCI state corresponds to CDM group #0,and the second TCI state corresponds to CDM group #1. In the case thatthree or more TCI states and three or more CDM groups are indicated tothe UE, a CDM group may be sequentially mapped to a TCI state accordingto an index order of the CDM groups. For example, in the case that TCIstates 1,2, and 3 are indicated to the UE and CDM groups 0,1, and 2 areindicated to the UE, TCI state 1 may correspond to CDM group 0, TCIstate 2 may correspond to CDM group 1, and TCI state 3 may correspond toCDM group 3.

In addition, while an order of TCI state configured to the UE is fixed,it may be defined such that the total number of layers are the same butthe number of layers corresponding to each CDM group is different tosupport a combination of the number of layers corresponding to each TRPin various manners.

Table 13 represent an example of a DMRS table in which the total numberof layers corresponding to each TRP are the same but the number oflayers corresponding to each CDM group is different. In Table 13, thecase in which dmrs-Type=1 and maxLength=2 is assumed.

TABLE 13 One Codeword: Codeword 0 enabled, Codeword 1 disabled Number ofDMRS CDM DMRS Mumber of front- Value group(s) without data port(s) loadsymbols 0 2 0, 1, 6 2 1 2 2, 3, 4 2

Referring to Table 13, a combination of the number of layers for CDMgroup #0: CDM group #1 is (2:1) in the case that ‘value’ is 0, and (1:2)in the case that ‘value’ is 1. This has an advantage that an order of aTCI state may be fixedly configured to the UE (e.g., {TCI state #1, TCIstate #2}), and various layer combinations, that is, (2:1) or (1:2) maybe supported through a DMRS port indication.

However, in the case that multiple-user (MU) together with multiple-TRPtransmission are assumed, a problem may occur in Alt 1 scheme, that is,the scheme that the first TCI state fixedly corresponds to CDM group #0,and the second TCI state fixedly corresponds to CDM group #1. Forexample, in the case that only {TCI state #1, TCI state #2} isconfigured to both UE 1 and UE 2, and UE 1 and UE 2 are intended toreceive data from TRP #1 (TCI state #1) and TRP #2 (TCI state #2) in(2:1) layer combination, the corresponding transmission may not beperformed according to the DMRS table (e.g., Table 13).

In order to solve the problem described above, additional TCI statessuch as {TCI state #2, TCI state #1} need to be configured to all UEs,but overhead increases due to the additional TCI state configuration.Hereinafter, Alt 2 proposes a method for solving the problem withoutadditional TCI state configuration in the case that multiple-user (MU)together with multiple-TRP transmission are assumed.

Alt 2: In the case that multiple TCI states are indicated in a TCI statefield in DCI to the UE, a CDM group order may be implicitly indicated tothe UE according to orders of DMRS ports indicated to the UE. Forexample, a part or the whole DMRS port(s) among the DMRS portscorresponding to the same CDM group may be referred to as a DMRS portset, and a DMRS port(s) combination indicated to the UE based on a DMRStable may be defined as multiple DMRS port sets in a unit of the DMRSport set. The CDM group order of Alt 2 may be the same as the order ofthe CDM group corresponding to the DMRS port set indicated to the UE,and each TCI state may sequentially correspond to the CDM group order.

Table 14 represents an example of a new DMRS table consideringmultiple-TRP transmissions and multiple users to which the presentproposed method is applicable. Table 14 is just an example for theconvenience of description, and not intended to limit the technicalscope of the present disclosure.

TABLE 14 One Codeword: Codeword 0 enabled, Codeword 1 disabled Number ofDMRS Number of CDM group(s) DMRS front-load Value without data port(s)symbols 0 2 0, 1, 6 2 1 2 2, 3, 4 2 2 2 6, 0, 1 2 3 2 4, 2, 3 2

Referring to Table 14, ‘Value’ 0 or 2 indicates the same DMRS port butthe explicit order is different. In the case that ‘Value’ is 0 or 3,there is an effect that an order for CDM group #0 and CDM group #1 isindicated through the order of DMRS port, and in the case that ‘Value’is 1 or 2, there is an effect that an order for CDM group #1 and CDMgroup #0 is indicated through the order of DMRS port. Furthermore, inthe case that ‘Value’ is 0 or 3, the first TCI state may be mapped toCDM group #0 indicated as the first CDM group, and the second TCI statemay be mapped to CDM group #1 indicated as the second CDM group, throughthe order of DMRS port. On the other hand, in the case that ‘Value’ is 1or 2, the first TCI state may be mapped to CDM group #1 indicated as thefirst CDM group, and the second TCI state may be mapped to CDM group #0indicated as the second CDM group, through the order of DMRS port.

That is, in the case that multiple TCI states are indicated, the firstTCI state may correspond to the first CDM group, and the second TCIstate may correspond to the second CDM group, through the order of DMRSport. In the case that such an operation is available, when value 0 isindicated to UE 1 and value 1 is indicated to UE 2, both UE 1 and UE 2may simultaneously receive data from TRP #1 (TCI state #1) by 2 layersand from TRP #2 (TCI state #2) by 1 layer (i.e., MU state).

In other words, a part or the whole DMRS port(s) among the DMRS portscorresponding to the same CDM group may be referred to as a DMRS portset, and a DMRS port(s) combination indicated to the UE based on a DMRStable may be defined as multiple DMRS port sets in a unit of the DMRSport set. The CDM group order of the proposal may be the same as theorder of the CDM group corresponding to the DMRS port set indicated tothe UE, and each TCI state may sequentially correspond to the CDM grouporder.

For example, a case that {TCI state A, TCI state B} is indicated to theUE may be assumed. In the case that DMRS port 0 (CDM group 0), 1 (CDMgroup 0), and 6 (CDM group 1) are indicated to the UE, DMRS port 0/1 maybe referred to as the first DMRS port, and the corresponding CDM group 0may be referred to as the first CDM group. Furthermore, DMRS port 6 maybe referred to as the second DMRS port, and the corresponding CDM group1 may be referred to as the second CDM group. Accordingly, the first TCIstate, TCI state A may correspond to CDM group 0, the first CDM group(or DMRS port(s) included in CDM group 0), and the second TCI state, TCIstate B may correspond to CDM group 1, the second CDM group (or DMRSport(s) included in CDM group 1).

On the contrary, in the case that DMRS port 6 (CDM group 1), 0 (CDMgroup 0), and 1 (CDM group 0) are indicated to the UE, DMRS port 6 maybe referred to as the first DMRS port, and the corresponding CDM group 1may be referred to as the first CDM group. Furthermore, DMRS port 0/1may be referred to as the second DMRS port, and the corresponding CDMgroup 0 may be referred to as the second CDM group. Accordingly, thefirst TCI state, TCI state A may correspond to CDM group 1, the firstCDM group (or DMRS port(s) included in CDM group 1), and the second TCIstate, TCI state B may correspond to CDM group 0, the second CDM group(or DMRS port(s) included in CDM group 0).

In addition, the scheme may also be applied to the case of 2-codeword(CW) (e.g., first CW and second CW). Table 15 represents an example of aDMRS table for 2CW transmission. In Table 15, the case that dmrs-Type=1and maxLength=2 is assumed.

TABLE 15 Two Codewords: Codeword 0 enabled, Codeword 1 enabled Number ofDMRS Number of CDM group(s) DMRS front-load Value without data port(s)symbols 0 2 2, 3, 0, 1, 4 2 1 2 0, 1, 2, 3, 5 2

Referring to Table 15, in the case that ‘Value’ is 0, there is an effectthat an order for CDM group #1 and CDM group #0 is indicated through theorder of DMRS port, and in the case that ‘Value’ is 1, there is aneffect that an order for CDM group #0 and CDM group #1 is indicatedthrough the order of DMRS port. Furthermore, in the case that ‘Value’ is0, the first TCI state may be mapped to CDM group #1 indicated as thefirst CDM group, and the second TCI state may be mapped to CDM group #0indicated as the second CDM group, through the order of DMRS port. Onthe other hand, in the case that ‘Value’ is 1, the first TCI state maybe mapped to CDM group #0 indicated as the first CDM group, and thesecond TCI state may be mapped to CDM group #1 indicated as the secondCDM group, through the order of DMRS port.

Meanwhile, in 2-CW case, the number of DMRS ports in a CDM groupindicated as the first CDM group and the number of DMRS ports in a CDMgroup indicated as the second CDM group are fixed to a specific number.The specific number may be changed depending on the total number oftransmission layers. This is the property that needs to be consideredsince the TCI states are sequentially mapped to layers according to anorder of the DMRS port indicated to the UE. In addition, in 2-CWtransmission case, different CWs may correspond to different TRPs (i.e.,TCI states). This is because a transmission most proper to a channel foreach TRP may be performed for each CW.

As represented in the example of Table 15 above, for 5-layertransmission, the number of layers mapped to each CW is fixed to 2layers and 3 layers with respect to a first CW (CW #0) and a second CW(CW #1), respectively. Accordingly, the number of DMRS ports in a CDMgroup indicated as the first CDM group needs to be fixed to 2 layers,and the number of DMRS ports in a CDM group indicated as the second CDMgroup needs to be fixed to 3 layers. The fixed combination of the numberof layers described above may be defined as (the number of DMRS ports inthe first CDM group:the number of DMRS ports in the second CDM group).For example, in the case of the whole number of transmission layers 6,7, and 8, the combination may be defined as (3:3), (3:4), and (4:4),respectively.

First Embodiment

In the case that multiple TCI states are indicated in a TCI state fieldin DCI to the UE, a CDM group order may be implicitly indicated to theUE according to orders of DMRS ports indicated to the UE. For example,an order of the CDM group may be determined according to the first DMRSport among the DMRS ports indicated to the UE through a DMRS table. Thatis, the CDM group including the first DMRS port among the DMRS portsindicated to the UE through a DMRS table or the CDM group correspondingto the first DMRS port may be defined as the first CDM group, and theremaining CDM group(s) (including the remaining DMRSport(s)/corresponding CDM group(s)) may be defined as the second CDMgroup(s). The DMRS ports corresponding to the first CDM group maycorrespond to the first TCI state, and the DMRS portscorresponding/related to the second CDM group(s) may correspond to thesecond TCI state.

Table 16 to Table 19 represent examples that an order of CDM group isdetermined according to an (indication) order of a DMRS port. Table 16to Table 19 represent examples of the first CDM group and the second CDMgroup for a DMRS port combination to which 2 CDM groups are indicatedbased on the DMRS table defined in TS38.212 and Table 7.4.1.1.2-1/2(Table 11 and Table 12 above) defined in TS 38.211.

TABLE 16 Based on table 7.3.1.2.2.-1 in TS38.212, One Codeword DMRS thefirst indicated the second indicated Value port(s) CDM group CDM group 9 0-2 CDM group 0 CDM group 1 10 0-3 CDM group 0 CDM group 1 11 0, 2CDM group 0 CDM group 1

TABLE 17 Based on table 7.3.1.2.2.-2 in TS38.212, Based on table7.3.1.2.2.-2 in TS38.212, One Codeword Two Codeword the first the secondthe first the second DMRS indicated indicated DMRS indicated indicatedValue port(s) CDM group CDM group Value port(s) CDM group CDM group 90-2 CDM group 0 CDM group 1 0 0-4 CDM group 0 CDM group 1 10 0-3 CDMgroup 0 CDM group 1 1 0, 1, 2, 3, 4, 6 CDM group 0 CDM group 1 11 0, 2CDM group 0 CDM group 1 2 0, 1, 2, 3, 4, 5, 6 CDM group 0 CDM group 1 300, 2, 4, 6 CDM group 0 CDM group 1 3 0, 1, 2, 3, 4, 5, 6, 7 CDM group 0CDM group 1

TABLE 18 Based on table 7.3.1.2.2.-3 in TS38.212, One Codeword DMRS thefirst indicated the second indicated Value port(s) CDM group CDM group 9 0-2 CDM group 0 CDM group 1 10 0-3 CDM group 0 CDM group 1 20 0-2 CDMgroup 0 CDM group 1 21 3-5 CDM group 1 CDM group 2 22 0-3 CDM group 0CDM group 1 23 0, 2 CDM group 0 CDM group 1

TABLE 19 Based on table 7.3.1.2.2.-4 in TS38.212, Based on table7.3.1.2.2.-4 in TS38.212, One Codeword Two Codeword the first the secondthe first the second DMRS indicated indicated DMRS indicated indicatedValue port(s) CDM group CDM group Value port(s) CDM group CDM group 90-2 CDM group 0 CDM group 1 2 0, 1, 2, 3, 6 CDM group 0 CDM group 1 100-3 CDM group 0 CDM group 1 3 0, 1, 2, 3, 6, 8 CDM group 0 CDM group 120 0-2 CDM group 0 CDM group 1 4 0, 1, 2, 3, 6, 7, 8 CDM group 0 CDMgroup 1 21 3-5 CDM group 1 CDM group 2 5 0, 1, 2, 3, 6, 7, 8, 9 CDMgroup 0 CDM group 1 22 0-3 CDM group 0 CDM group 1 23 0, 2 CDM group 0CDM group 1

Referring to Table 16 to Table 19, in the DMRS port combination, the CDMgroup corresponding to the first DMRS port may be determined to be thefirst CDM group.

For example, two types of DMRS port combination (0,1,2) and (2,0,1) isconfigured with the same DMRS ports, but the order of indicated CDMgroup may be different. The CDM groups included in/corresponding to DMRSport (0, 1, 2) and (2, 0, 1) are the same as CDM group 0 and CDM group1, respectively (refer to Table 11 and Table 12), but the first DMRSport is different as 0 and 2. Accordingly, the group order may bedifferently indicated/configured such that the first CDM group of thefirst DMRS port combination (i.e., (0,1,2)) is CDM group 0 thatcorresponds to the first DMRS port 0, and the first CDM group of thesecond DMRS port combination (i.e., (2, 0, 1)) is CDM group 1 thatcorresponds to the first DMRS port 2.

Accordingly, in the case of the DMRS port combination (0,1,2), DMRSports 0, 1, which are DMRS port(s) of CDM group 0 may correspond to thefirst TCI state, and DMRS port 2 corresponding to CDM group 1 maycorrespond to the second TCI state. On the other hand, in the case ofthe DMRS port combination (2,0,1), DMRS ports 2, which is DMRS port ofCDM group 1 may correspond to the first TCI state, and DMRS ports 0, 1,which are DMRS port(s) of CDM group 0 may correspond to the second TCIstate.

For example, as described above, it may be indicated/configured/promisedthat when the number of CDM groups is 3, the DMRS port(s) includedin/corresponding to the CDM group corresponding to the DMRS port maycorrespond to the first TCI state, and the DMRS ports includedin/corresponding to the remaining two CDM groups may correspond to thesecond TCI state.

As described in Alt 2 and the first embodiment, for each of the DMRSport combinations configured with the same DMRS ports, different CDMgroup order may be indicated based on the orders of DMRS ports, andtherefore, a mapping relation between a TCI state and a DMRS port and amapping relation between a TCI state and a CDM group may be changed.

Meanwhile, layer x(i)=[x⁽⁰⁾(i) . . . x^((υ-1))(i)]^(T), i=0, 1, . . . ,M_(symb) ^(layer)−1 is mapped to antenna ports according to Equation 5.Herein, v represents the number of layers, and M_(symb) ^(layer)represents the number of modulation symbols per layer.

$\begin{matrix}{{{{\begin{bmatrix}{y^{(p_{0})}(i)} \\\vdots \\{y^{(p_{o - 1})}(i)}\end{bmatrix}\begin{bmatrix}{x^{(0)}(i)} \\\vdots \\{x^{({o - 1})}(i)}\end{bmatrix}}\mspace{14mu}{where}\mspace{14mu} i} = 0},1,\ldots\;,{M_{symb}^{ap} - 1},{M_{symb}^{ap} = M_{symb}^{layer}}} & \lbrack {{Equation}\mspace{14mu} 5} \rbrack\end{matrix}$

The set {p₀ . . . , p_(υ-1)} of antenna ports may be determinedaccording to the procedure of [TS 38.212]. That is, the set may besequentially mapped to layers according to orders of DMRS portsindicated to the UE through a DMRS table.

Considering Equation 5, two types of DMRS port combination (0,1,2) and(2,0,1) is configured with the same DMRS ports, but a mapping relationbetween a DMRS port and a layer may be different. For example, the firstDMRS port combination (i.e., (0,1,2)) is mapped to number 0, 1, and 2layer, respectively, according to the DMRS port order of number 0, 1,and 2, but the second DMRS port combination (i.e., (2, 0, 1)) is mappedto number 0, 1, and 2 layer, respectively, according to the DMRS portorder of number 2, 0, and 1. In this case, in the aspect of UEimplementation, different DMRS port to layer mapping relations need tobe defined.

Assuming that the two different types of DMRS port combination isintended to indicate different mapping relation between DMRS ports andTCI states, it may be defined that the mapping relation between DMRSports and layers is the same. That is, in the case that orders of DMRSports indicated through a DMRS table is different, but the DMRS portsincluded in the DMRS port combination are the same, it may be definedthat the same DMRS port to layer mapping relation is assumed even fordifferent DMRS port combination.

For example, regardless of the order in which DMRS ports are indicated,the DMRS port of low index may be mapped from a layer of low indexsequentially. That is, in the above example, it may be assumed that DMRSport n is mapped to layer n. As a specific example, for two types ofDMRS port combination (0,1,2) and (2,0,1), there is a specific mappingrelation of DMRS port to layer, and an assumption of mapping relation ofDMRS port to layer may be defined/configured such that DMRS port 0corresponds to layer 0, DMRS port 1 corresponds to layer 1, and DMRSport 2 corresponds to layer 2.

As such, when DMRS ports configuring a DMRS port combination are thesame, in the case that the same mapping relation of DMRS port to layeris assumed without regard to orders of DMRS ports configuring a DMRSport combination, the UE may not implement an additional mappingrelation of DMRS port to layer, and accordingly, UE implementationalcomplexity may be decreased.

Furthermore, in the case that three or more TCI states and three or moreCDM groups are indicated to the UE, a mapping relation between a TCIstate and a CDM group (i.e., DMRS port(s)) may be determined accordingto an order of DMRS port which is firstly present in each CDM groupbased on orders of DMRS ports in a DMRS port combination indicated tothe UE.

For example, in the case that TCI states 1, 2, and 3 are indicated tothe UE and DMRS ports 2, 3, 0, 1, 4, and 5 (assuming type 2 DMRS) areindicated, a mapping relation between a TCI state and a CDM group may bedetermined according to an order among 2, 0, and 4, which are DMRS portsfirstly present in each CDM group. That is, TCI state 1 may correspondto CDM group 1, which is the first CDM group that corresponds to thefirst DMRS port 2. TCI state 2 may correspond to CDM group 0, which isthe second CDM group, and TCI state 3 may correspond to CDM group 2,which is the third CDM group.

Alt 3: In the case that multiple TCI states are indicated in a TCI statefield in DCI to the UE, the CDM group of the lowest (or highest) indexamong the CDM groups indicated to the UE may correspond to the first TCIstate, and the remaining TCI group may correspond to the second TCIstate. Alternatively, the CDM group of the lowest (or highest) indexamong the CDM groups indicated to the UE may correspond to the secondTCI state, and the remaining TCI group may correspond to the first TCIstate. That is, it may be configured/indicated/promised such that theDMRS port(s) included in a CDM group of the lowest (or highest) indexamong the CDM groups indicated by the DMRS port(s) (corresponding to theDMRS port) indicated to the UE may correspond to the first (or second)TCI state, and the DMRS port(s) corresponding to the remaining CDM groupamong the DMRS port(s) may correspond to the second (first) TCI state.

As a specific example, for two different types of DMRS port combination(0,1,2) and (2,0,1), the CDM group of the lowest index is CDM group 0for both the first combination (e.g., (0, 1, 2)) and the secondcombination (e.g., (2, 0, 1)). Accordingly, in both two combinations,the first CDM group may correspond to CDM group 0, and the second CDMgroup may correspond to CDM group 1. In addition, in both twocombinations, the DMRS port corresponding to the first TCI state is 0and 1, and the DMRS port corresponding to the second TCI state is 2.

On the other hand, for two different types of DMRS port combination(0,1,2) and (2,0,1), the CDM group of the lowest index is CDM group 0for both the first combination (e.g., (0, 1, 2)) and the secondcombination (e.g., (2, 0, 1)), and accordingly, in both twocombinations, the first CDM group may correspond to CDM group 0, and thesecond CDM group may correspond to CDM group 1. In the firstcombination, the DMRS port of CDM group 0 corresponding to the first TCIstate is 0 and 1, and the DMRS port of CDM group 1 corresponding to thesecond TCI state is 2. On the other hand, in the second combination, theDMRS port of CDM group 0 corresponding to the first TCI state is 1, andthe DMRS port of CDM group 1 corresponding to the second TCI state is 2and 3. In this case, using different DMRS port combinations, the casethat the number of DMRS ports corresponding to each TCI state isdifferent may be supported.

Furthermore, the mapping relation of DMRS port to layer may also beapplied to Alt 3. For example, regardless of the order in which DMRSports are indicated, the DMRS port of low index may be mapped from alayer of low index sequentially.

<Proposal 4>

I may be indicated/configured that A single user (SU) dedicated DMRSport combination among the DMRS port combination in Rel-15 DMRS tablemay be used for multiple-user (MU) usage through implicit or explicitDCI signaling and/or higher layer signaling.

In Rel-15 TS 38.214 5.1.6.2 section, the single user (SU) dedicated DMRSport combination is described as represented in Table 20.

TABLE 20 For DM-RS configuration type 1,  - if a UE is scheduled withone codeword and assigned with the antenna port mapping with indices of{2, 9, 10, 11 or 30} in Table 7.3.1.2.2-1 and Table 7.3.1.2.2-2 ofSubclause 7.3.1.2 of [5, TS 38.212], or  - if a UE is scheduled with twocodewords, the UE may assume that all the remaining orthogonal antennaports are not associated with transmission of PDSCH to mother UE. ForDM-RS configuration type 2,  - if a UE is scheduled with one codewordand assigned with the antenna port mapping with indices of {2, 10 or 23}in Table 7.3.1.2.2-3 and Table 7.3.1.2.2-4 of Subclause 7.3.1.2 of [5,TS38.212], or  - if a UE is scheduled with two codewords, the UE mayassume that all the remaining orthogonal antenna ports are notassociated with transmission of PDSCH to another UE.

Referring to Table 20, the “SU dedicated DMRS port combination among theDMRS port combination in Rel-15 DMRS table” may mean a DMRS portcombination in which the DMRS port(s) excluding the DMRS port(s)allocated to the UE is not allocated another UE except the UE within theCDM group(s) to which the DMRS port(s) allocated to the UE belongs. Forexample, for DMRS configuration type 1 case, the DMRS port(s)corresponding to {2,9,10,11,30} value in the DMRS table may be a SUdedicated DMRS port combination.

In the proposal, “may be used for multiple-user (MU) usage” may mean asituation in which a DMRS port except the DMRS port allocated to thespecific UE may not be allocated to another UE except the specific UE,that is, may be allocated to another UE. In the case that “SU dedicatedDMRS port combination may be used for MU usage” is indicated/configured,the operation change may occur in the aspect of UE.

In the case that the UE may know SU dedicated DMRS port combination, CDMmay not be considered in channel estimation. This means that it may benot considered that different DMRS ports are multiplexed in time domainand/or frequency domain using an orthogonal sequence. In the case of notconsidering CDM, the UE may utilize all reference signals received intime domain and/or frequency domain for interpolation, and accordingly,there is an advantage that a sample value for utilizing in channelestimation may increase and channel estimation performance may beimproved.

On the other hand, in the case that “SU dedicated DMRS port combinationmay be used for MU usage” is indicated/configured, the UE may not assumesuch an assumption. The UE needs to consider interference due to theDMRS port usable by another UE in channel estimation and consider CDM intime domain and/or frequency domain to remove the interference. In orderto estimate a channel corresponding to each DMRS port, a process ofremoving a channel value for the DMRS port that may act as interferenceis required, and owing to the process, the number of sample values whichmay actually utilized for interpolation may decrease. Consequently,owing to the process, degradation may occur in channel estimationperformance.

In a multiple TRP transmission situation, the DMRS ports correspondingto different TRPs may correspond to different CDM groups. For example,in the case that the total number of transmission layers is 2, layer #0that corresponds to TRP #1 may correspond to DMRS port 0 correspondingto CDM group #0, and layer #1 that corresponds to TRP #2 may correspondto DMRS port 2 corresponding to CDM group #1. In the case that the BS isintended to apply multiple TRP transmission, the BS may indicate a DMRSport combination configured with DMRS ports included in different CDMgroups. For example, the following examples may be exemplified for theDMRS port combination configured with DMRS ports included in differentCDM groups in the DMRS table (e.g., 3gpp TS38.212 Tables7.3.1.2.2-1/2/3/4) defined in Rel-15.

For Table 7.3.1.2.2-1 corresponding to the case that dmrs-Type=1 andmaxLength=1 are configured, values 9, 10, and 11

For Table 7.3.1.2.2-2 corresponding to the case that dmrs-Type=1 andmaxLength=2 are configured, values 9, 10, 11, and 30

For Table 7.3.1.2.2-3 corresponding to the case that dmrs-Type=2 andmaxLength=1 are configured, values 9, 10, 20, 21, 22, and 23

For Table 7.3.1.2.2-4 corresponding to the case that dmrs-Type=2 andmaxLength=2 are configured, values 9, 10, 20, 21, 22, and 23

The characteristics of the DMRS port combinations are that many SUdedicated DMRS port combinations (refer to Table 20) are includedtherein. Particularly, the case of dmrs-Type=1 is characterized that allDMRS port combinations (DMRS port combinations corresponding values 9,10, and 11) that may support multiple TRP transmission are SU dedicatedDMRS port combinations without regard to the maxLength. Accordingly,there is a disadvantage that when the BS using dmrs-Type=1 schedulesmultiple TRP transmission on a specific UE, the UE may not schedule datatransmission in the same timing to another UE. In addition, even for thecase that dmrs-Type=2 is configured, since a part of DMRS portcombinations are included in SU dedicated DMRS port combination, alimitation occurs for supporting MU.

Accordingly, the scheme of Proposal 4 may be used as a method forcompensating the disadvantage that MU may not be supported when multipleTRP transmission is supported, and there is an advantage that MU issupported even in the case that multiple TRP transmission is supported,and accordingly, cell throughput may be improved. Hereinafter, a methodfor indicating/configuring that single user (SU) dedicated DMRS portcombination may be used for multiple user (MU) usage is described indetail.

SU dedicated DMRS port combination may be configured to be used for MUusage implicitly through DCI. In the case that multiple TCI states areindicated to a UE through a TCI state field in DCI, SU dedicated DMRSport combination in Rel-15 DMRS table (e.g., 3gpp TS38.212 Table7.3.1.2.2-1/2/3/4) may be used for MU usage. In other words, SUdedicated DMRS port combination may be indicated/configured to be usedfor MU usage based on the number of TCI states indicated through a TCIfield in DCI.

Alternatively, SU dedicated DMRS port combination may be configured tobe used for MU usage implicitly through higher layer signaling (e.g.,MAC CE). In the case that multiple TCI states are activated in one ormore code points among the code points corresponding to TCI field inDCI, in Rel-15 DMRS table, SU dedicated DMRS port combination (refer toTable 20) may be used for MU usage.

For example, in the case that ‘value’ 9 of Table 7.3.1.2.2-1 isindicated to a specific UE, DMRS port 3 is unable to be used for MUusage previously. However, according to the present proposal, i) in thecase that multiple TCI states are indicated to a UE through a TCI statefield in DCI or ii) in the case that multiple TCI states are activatedin one or more code points among the code points corresponding to TCIfield in DCI through higher layer signaling, DMRS port 3 may beadditionally used for MU usage. That is, the BS may configure DMRS port3 to another UE for MU usage, and the UE may assume that DMRS port 3 maybe configured to another UE (and/or assume that DMRS port 3 is not SUdedicated).

According to the operation of Proposal 4, whether an operation isperformed (i.e., activation/deactivation for whether SU dedicated DMRSport combination is used for MU usage) may be configured throughseparate higher layer signaling. For example, the operation of Proposal4 scheme may be activated through higher layer signaling, and i) in thecase that multiple TCI states are indicated to a UE through a TCI statefield in DCI or ii) in the case that multiple TCI states are activatedin one or more code points among the code points corresponding to TCIfield in DCI through higher layer signaling, SU dedicated DMRS portcombination may be used for MU usage. On the other hand, in the casethat the operation is deactivated, the UE may assume SU dedicated DMRSport combination in the same was as previously even in the case of i) orii).

As another method, the fact that SU dedicated DMRS port combination maybe used for MU usage may be indicated/configured through explicitsignaling. For example, a specific higher layer parameter and/or a DCIfield configuring/indicating that SU dedicated DMRS port combination maybe used for MU usage is introduced in Rel-15 DMRS table, and the factmay be explicitly configured. Furthermore, whether the UE can configurea higher layer parameter and/or a DCI field may be configured/determinedby UE capability.

Meanwhile, the scheme of Proposal 4 may be limitedly applied to a partof situations. For example, the scheme of Proposal 4 may be limitedly to1 CW transmission case.

<Proposal 5>

As described above, in the current standard, a DL (downlink) PTRSdefines a maximum of 1 port transmission. Particularly, when the UE isscheduled with one codeword), a PTRS port is associated with a DMRS portof the lowest index among scheduled DMRS ports allocated for a PDSCH.When the UE is scheduled with two codewords, the PTRS port is associatedwith the DMRS port of the lowest index among the DMRS ports allocatedfor a codeword having a higher MCS. In the case that MCS indexes of twocodewords are the same, the PTRS port is associated with the DMRS portof the lowest index allocated for codeword 0. For the DL DMRS portassociated with the PTRS port, quasi co-located is assumed in the aspectof {QCL type A and QCL type D}.

However, in the case that multiple-TRP/panel transmission is considered,a phase source may be different between different TRPs/panels, andaccordingly, a different PTRS port needs to be defined in each TRP/panelto compensate phase noise influence occurred from different TRPs/panels.Alternatively, in the case of multiple-panel, panels may have the samephase source, and in this case, a single PTRS port is sufficient. Assuch, even in the case that multiple-TRP/panel transmission is assumed,the number of required PTRS ports may be changed depending on asituation.

Accordingly, in Proposal 5, considering the case that a BS performsmultiple-TRP/panel transmission, a method for configuring the number ofPTRS ports to a UE is proposed. The number of PTRS ports may bedetermined based on at least one of (i) the maximum number of DL PTRSports configurable (configured) to a UE, (ii) the number of TCI statesindicated through DCI, or (iii) the number of CDM groupsincluding/corresponding to a DMRS port(s) indicated through DCI.

The BS may configure the maximum number of DL PTRS ports through ahigher layer configuration. For example, in the case that the BSperforms multiple-TRP/panel transmission, the maximum number of DL PTRSports may be configured through a higher layer configuration. In oneexample, as the higher layer configuration, PTRS-DownlinkConfig IEconfigured through RRC may be used.

An actual number of DL PTRS ports to be transmitted to the UE may bedetermined based on the number of TCI states indicated to the UE throughDCI (this may mean specific code points of TCI state field) and/or thenumber of CDM groups including the DMRS ports(s) indicated through DCI(this may mean specific entry/code points of DMRS indication field)together with the higher layer configuration (e.g.,PTRS-DownlinkConfig). This because the number of TCI states indicated tothe UE through DCI or the number of CDM groups including the DMRSports(s) indicated through DCI may be changed depending on whether it issingle-TRP/panel transmission or multiple-TRP/panel transmission.

For example, in the case that the maximum number of DL PTRS ports isconfigured to 1 to the UE through a higher layer configuration, 1 portPTRS may be transmitted. In the case that the maximum number of DL PTRSports is configured to a number greater than 1 to the UE, the actualnumber of DL PTRS ports transmitted to the UE may be determined based onthe maximum number of DL PTRS ports configured through a higher layerconfiguration, the number of TCI states indicated through DCI to the UE,and the number of CDM groups corresponding to a DMRS port(s) indicatedthrough DCI.

For example, in the case that the number of CDM groups including a DMRSport(s) indicated through DCI is 1, the number of DL PTRS ports actuallytransmitted may correspond to 1, and in the case that the number of CDMgroups including a DMRS port(s) indicated through DCI is 2 or greater,the number of DL PTRS ports may be determined to be a minimum valueamong the maximum number of DL PTRS ports configured to the UE, and/orthe number of TCI states indicated through DCI, and/or the number of CDMgroups including a DMRS port(s) indicated through DCI.

For example, even in the case that multiple TCI states is indicated,only the DMRS port(s) included in a single CDM group may be indicated,which may mean single-TRP/panel transmission. In this case, a singlePTRS port is sufficient, and 1 port PTRS corresponding to minimum value1 may be transmitted among the maximum number of DL PTRS portsconfigured through a higher layer configuration, the number of TCIstates indicated through DCI, or the number of CDM groups correspondingto a DMRS port(s) indicated through DCI. On the other hand, in the casethat multiple TCI states and a DMRS port(s) included in a plurality ofCDM groups are indicated, this may mean multiple-TRP/panel transmission.In this case, the number of PTRS ports needs to be defined as many asthe number of TRPs/panels of which phase source is different.Accordingly, the number of the PTRS ports may correspond to a minimumvalue among the maximum number of DL PTRS ports configured to the UE,and/or the number of TCI states indicated through DCI, and/or the numberof CDM groups including a DMRS port(s) indicated through DCI.

Meanwhile, the maximum number of DL PTRS ports may be configured foreach code-point of a TCI state field in DCI. This is because differentTCI state combination may be mapped to each code-point of a TCI field inDCI. For example, each of a code-point corresponding tosingle-TRP/panel, a code-point corresponding to multiple-TRP/panel withdifferent phase source, and a code-point corresponding tomultiple-TRP/panel with the same phase source may be configured. In thiscase, in order to define/configure the number of PTRS ports optimizedfor each code-point, different maximum number of DL PTRS ports may beconfigured for each code-point.

For example, 1 port PTRS may be configured to the code-pointcorresponding to single-TRP/panel, 2 port PTRS may be configured to thecode-point corresponding to multiple-TRP/panel with different phasesource, and 1 port PTRS may be configured to the code-pointcorresponding to multiple-TRP/panel with the same phase source. In orderto configure different maximum number of DL PTRS ports for eachcode-point of a TCI state field in DCI, a method of using MAC CEsignaling may be considered.

FIG. 12 illustrates an example of a message (e.g., MAC CE) foractivation/deactivation of TCI states for UE-specific PDSCH MAC CEdefined in TS38.321.

Referring to FIG. 12, in the message (e.g., MAC CE), T_i is a fieldindicating activation/deactivation state of TCI state having TCI-StateIdi. A bit corresponding to T_i may configured to 0 or 1, and T_iconfigured to 1 may indicate that the TCI state having TCI-StateId i isactivated and corresponds/is mapped to the code-points of a TCI statefield in DCI. In order to configure the maximum number of DL PTRS portscorresponding to each code-point, additional bits may be allocatedand/or a new message may be defined together with the message ofactivating the TCI states.

For example, based on information of bitmap format, the maximum numberof PTRS ports may be configured for each code-point. The maximum numberof DL PTRS ports corresponding to 0 and 1 of bitmap may be predefined.Additional bits for the information of bitmap format may be allocated,or a new message (e.g., MAC CE) may be defined. As a specific example,since 3 bits are allocated to a TCI field of DCI format 1_1, a total of8 code-points including 000, 001, . . . , and 111 may be present. In thecase that a bit is 0 in 8-bit bitmap, in the case that the maximumnumber of DL PTRS ports is 1, 1, the maximum number of DL PTRS ports maycorrespond to 2, respectively. In addition, each bit of 8-bit bitmap maycorrespond to code-points 000, 001, . . . , and 111 of a TCI state fieldsequentially from LSB or MSB.

Even in the case that different maximum number of DL PTRS ports isconfigured for each code-point of a TCI state field in DCI, the numberof PTRS ports through which PTRS is actually transmitted may bedetermined according to the number of CDM groups including a DMRSport(s) indicated to the UE through DCI. This is because the number ofCDM groups including a DMRS port(s) indicated to the UE through DCI maybe changed depending on whether it is single-TRP/panel transmission ormultiple-TRP/panel transmission as described above.

For example, even in the case that a code-point of a TCI state field inwhich the maximum number of PTRS ports is configured to 2 is indicatedto the UE, only the DMRS port(s) included in a single CDM group may beindicated, which may means is single-TRP/panel transmission. In thiscase, a single PTRS port may be sufficient, and 1 port PTRScorresponding to minimum value 1 may be transmitted among the maximumnumber of DL PTRS ports configured to a code-point of a TCI state fieldindicated to the UE or the number of CDM groups including a DMRS port(s)indicated through DCI. On the other hand, even in the case that acode-point of a TCI state field in which the maximum number of PTRSports is configured to 1 is indicated to the UE, the DMRS port(s)included in a plurality of CDM groups may be indicated, which may meanmultiple-TRP/panel transmission using the same phase source.Accordingly, even in this case, a single PTRS port may be sufficient,and as the number of PTRS ports actually transmitted, 1 port PTRScorresponding to minimum value 1 may be transmitted among the maximumnumber of DL PTRS ports configured to a code-point of a TCI state fieldindicated to the UE or the number of CDM groups including a DMRS port(s)indicated through DCI.

Meanwhile, in the case that a code-point of a TCI state field in whichthe maximum number of PTRS ports is configured to 2 is indicated to theUE, and in the case that the DMRS port(s) included in a plurality of CDMgroups is indicated, which may mean multiple-TRP/panel transmissionusing different phase sources. Accordingly, in this case, the number ofPTRS ports needs to be defined as many as the number of TRPs/panels ofwhich phase source is different, and the number of the PTRS ports maycorrespond to a minimum value among the maximum number of DL PTRS portsconfigured to a code-point of a TCI state field indicated to the UE orthe number of CDM groups including a DMRS port(s) indicated through DCI.

FIG. 13 shows signaling in the case that a UE receives single DCI (i.e.,a single TRP transmits DCI to a UE) in M-TRP (or cell, hereinafter, allTRPs may be substituted by cells, or the case of configuring multipleCORESETs (/CORESET group) from a single TRP may be assumed to be M-TRP)situation. In FIG. 13, the case that TRP 1 is a representative TRP fortransmitting DCI is assumed. However, such an assumption is not intendedto limit the technical scope of the present disclosure.

Hereinafter, the description is described based on “TRP”, but asdescribed above, “TRP” may be substituted and applied by the expressionsuch as a panel, an antenna array, a cell (e.g., macro cell/smallcell/pico cell, etc.), a TP (transmission point), a base station (gNB,etc.). In addition, as described above, the TRP may be distinguishedaccording to information (e.g., index or ID) for a CORESET group (orCORESET pool). In one example, in the case that a single UE isconfigured to perform transmission/reception with multiple TRPs (orcells), this may mean that multiple CORESET groups (or CORESET pools)may be configured for the UE. A configuration for the CORESET group (orCORESET pool) may be performed through higher layer signaling (e.g., RRCsignaling).

The UE may receive configuration information for Multiple TRP basedtransmission/reception through/using TRP 1 (and/or TRP 2) from a Networkside (step S1305). That is, the Network side may transmit theconfiguration information related to Multiple TRP basedtransmission/reception through/using TRP 1 (and/or TRP 2) to the UE(step S1305). The configuration information may include informationrelated to configuration of network side (i.e., TRPconfiguration)/resource information (resource allocation) related toMultiple TRP based transmission/reception. The configuration informationmay be forwarded through higher layer signaling (e.g., RRC signaling,MAC-CE, etc.). In addition, in the case that the configurationinformation is predefined or preconfigured, the corresponding step maybe omitted. For example, the configuration information may includeconfiguration related to TCI state and/or DMRS port or DMRS table/PTRSport described in the method (e.g., Proposals 1/2/3/4/5, etc.) describedabove.

For example, the operation of the UE (100/200 shown in FIG. 16 to FIG.20) to receive the configuration information related to Multiple TRPbased transmission/reception from the Network side (100/200 shown inFIG. 16 to FIG. 20) of step S1305 described above may be implemented bythe apparatus shown in FIG. 16 to FIG. 20 to be described below. Forexample, referring to FIG. 17, one or more processors 102 may controlone or more transceivers 106 and/or one or more memories 104 to receivethe configuration information related to Multiple TRP basedtransmission/reception, and the one or more transceivers 106 may receivethe configuration information related to Multiple TRP basedtransmission/reception from the Network side.

Similarly, the operation of the Network side (100/200 shown in FIG. 16to FIG. 20) to transmit the configuration information related toMultiple TRP based transmission/reception to the UE (100/200 shown inFIG. 16 to FIG. 20) of step S1305 described above may be implemented bythe apparatus shown in FIG. 16 to FIG. 20 to be described below. Forexample, referring to FIG. 17, one or more processors 102 may controlone or more transceivers 106 and/or one or more memories 104 to transmitthe configuration information related to Multiple TRP basedtransmission/reception, and the one or more transceivers 106 maytransmit the configuration information related to Multiple TRP basedtransmission/reception.

The UE may receive DCI, and Data 1 scheduled by the DCI through/usingTRP 1 from the Network side (step S1310-1). In addition, the UE mayreceive Data 2 through/using TRP 2 from the Network side (step S1310-2).That is, the Network side may transmit DCI, and Data 1 scheduled by theDCI through/using TRP 1 to the UE (step S1310-1). In addition, theNetwork side may transmit Data 2 through/using TRP 2 to the UE (stepS1310-2). Here, the DCI may be configured to be used for scheduling bothData 1 and Data 2. In addition, for example, DCI and Data (e.g., Data 1,Data 2) may be transmitted through a control channel (e.g., PDCCH, etc.)and a data channel (e.g., PDSCH), respectively. In addition, stepS1310-1 and step S1310-2 may be simultaneously performed, or one of thesteps may be performed earlier than the other step.

For example, the DCI may include (indication) information for TCI state,resource allocation information for DMRS and/or data (i.e.,space/frequency/time resource) described in the above-described method(e.g., Proposals 1/2/3/4/5, etc.).

For example, the DCI may include i) a transmission configurationindication (TCI) field and ii) an antenna port field. For example, basedon the TCI field, a plurality of TCI states may be indicated. Inaddition, based on the antenna port field, DM-RS ports of a plurality ofCDM groups may be indicated. For example, the number of layersassociated with each CDM group may be differently configured.

For example, the DCI may include CRC (cyclic redundancy check) scrambledby a specific RNTI (Radio Network Temporary Identifier). In one example,the specific RNTI may be MCS-C-RNTI (modulation coding scheme cellRNTI). That is, the DCI may be associated with MCS-C-RNTI.

For example, the DCI may include information for the maximum number ofDL PTRS ports.

In addition, in this case, Data 1 and Data 2 may be transmitted andreceived based on TCI state/DMRS port/CDM group/layer/PTRS portdescribed in the above-described method (e.g., Proposals 1/2/3/4/5,etc.). For example, the Data 1 and the Data 2 may be received after aspecific offset from a reception timing.

For example, the operation of the UE (100/200 shown in FIG. 16 to FIG.20) to receive the DCI and/or the Data 1 and/or the Data 2 from theNetwork side (100/200 shown in FIG. 16 to FIG. 20) of stepsS1310-1/S1310-2 described above may be implemented by the apparatusshown in FIG. 16 to FIG. 20 to be described below. For example,referring to FIG. 17, one or more processors 102 may control one or moretransceivers 106 and/or one or more memories 104 to receive the DCIand/or the Data 1 and/or the Data 2, and the one or more transceivers106 may receive the DCI and/or the Data 1 and/or the Data 2 from theNetwork side.

Similarly, the operation of the Network side (100/200 shown in FIG. 16to FIG. 20) to transmit the DCI and/or the Data 1 and/or the Data 2 tothe UE (100/200 shown in FIG. 16 to FIG. 20) of steps S1310-1/S1310-2described above may be implemented by the apparatus shown in FIG. 16 toFIG. 20 to be described below. For example, referring to FIG. 17, one ormore processors 102 may control one or more transceivers 106 and/or oneor more memories 104 to transmit the DCI and/or the Data 1 and/or theData 2, and the one or more transceivers 106 may transmit the DCI and/orthe Data 1 and/or the Data 2 to the UE.

The UE may decode the Data 1 and the Data 2 received from TRP 1 and TRP2 (step S1315). For example, the UE may perform channel estimationand/or decoding the Data based on the above-described method (e.g.,Proposals 1/2/3/4/5, etc.).

The UE may know the number of CDM groups and the configuration of DM-RSport corresponding to a value of the antenna port field of the DCI basedon the predefined state information (or DMRS port related information)and may decode the Data 1 and the Data 2.

For example, it is assumed that based on the TCI field of the DCI,multiple TCI states are indicated, and based on the antenna port field,DM-RS ports of a plurality of CDM groups are indicated. Based on anindication order of the DMRS ports, orders of a plurality of CDM groupsmay be determined, and according to the determined orders of the CDMgroups, the multiple TCI states may be sequentially corresponded. Thefirst TCI state of the multiple TCI states may correspond to a CDM groupincluding the first DMRS port based on the indication order of the DMRSports.

In other words, based on the indication order of the DMRS ports, thefirst TCI state of the plurality of TCI states may correspond to a CDMgroup of the first DMRS port. In addition, the TCI states except thefirst TCI state may correspond to other CDM group except the CDM groupincluding the first DMRS port. Accordingly, the DMRS ports included inthe CDM group including the first DMRS port may be in QCL (Quasi colocation) relation with the reference signal related to the first TCIstate.

In still another example, in the case that the DCI is associated withMCS-C-RNTI, the DM-RS ports may correspond to the same DCI state. Basedon the condition that URLLC operation and multiple TCI states areindicated to the UE, each TCI state may correspond to a specificresource (e.g., at least one of time resource or frequency resource),and all DMRS ports indicated to the UE may correspond to the same TCIstate.

The DM-RS ports may be mapped to layers. For example, regardless of theorder in which DMRS ports are indicated, the DMRS ports may besequentially mapped to the layers based on indexes of the DM-RS ports.Alternatively, the DMRS ports may be sequentially mapped to the layersbased on indication orders.

For example, the operation of the UE (100/200 shown in FIG. 16 to FIG.20) to decode the Data 1 and the Data 2 of step S1315 described abovemay be implemented by the apparatus shown in FIG. 16 to FIG. 20 to bedescribed below. For example, referring to FIG. 17, one or moreprocessors 102 may control one or more memories 104 to decode the Data 1and the Data 2.

Based on the proposed method (e.g., Proposal 1/2/3/4/5, etc.), throughone or more PUCCH(s), the UE may transmit HARQ-ACK information (e.g.,ACK information, NACK information, etc.) for the DCI and/or the Data 1and/or the Data 2 using/through TRP 1 and/or TRP 2 to the Network side(steps S1320-1 and S1320-2). That is, based on the proposed method(e.g., Proposal 1/2/3/4/5, etc.), the Network side may receive HARQ-ACKinformation (e.g., ACK information, NACK information, etc.) for the DCIand/or the Data 1 and/or the Data 2 from the UE using/through TRP 1and/or TRP 2 (steps (S1320-1 and S1320-2).

For example, HARQ-ACK information for the Data 1 and/or the Data 2 maybe combined or separated depending on the number of codewords. Inaddition, the UE may be configured to transmit HARQ-ACK information to arepresentative TRP (e.g., TRP 1), and HARQ-ACK information transmissionto another TRP (e.g., TRP 2) may be omitted.

For example, the operation of the UE (100/200 shown in FIG. 16 to FIG.20) to transmit HARQ-ACK information for the Data 1 and/or the Data 2 tothe Network side (100/200 shown in FIG. 16 to FIG. 20) of stepsS1320-1/S1320-2 described above may be implemented by the apparatusshown in FIG. 16 to FIG. 20 to be described below. For example,referring to FIG. 17, one or more processors 102 may control one or moretransceivers 106 and/or one or more memories 104 to transmit HARQ-ACKinformation for the Data 1 and/or the Data 2, and the one or moretransceivers 106 to transmit HARQ-ACK information for the Data 1 and/orthe Data 2 to the Network side through one or more PUCCHs.

Similarly, the operation of the Network side (100/200 shown in FIG. 16to FIG. 20) to receive HARQ-ACK information for the Data 1 and/or theData 2 from the UE (100/200 shown in FIG. 16 to FIG. 20) of stepsS1320-1/S1320-2 described above may be implemented by the apparatusshown in FIG. 16 to FIG. 20 to be described below. For example,referring to FIG. 17, one or more processors 102 may control one or moretransceivers 106 and/or one or more memories 104 to receive HARQ-ACKinformation for the Data 1 and/or the Data 2, and the one or moretransceivers 106 may receive HARQ-ACK information for the Data 1 and/orthe Data 2 from the UE through one or more PUCCHs.

In FIG. 13, the single DCI based M-TRP operation is mainly described butmay be applied to the multiple-DCI based M-TRP operation in some cases.

FIG. 14 illustrates an example of PTRS reception operation flowchart ofa User Equipment (UE) to which the method (e.g., Proposal 1/2/3/4/5,etc.) proposed in the present disclosure may be applied. The UE may besupported by multiple TRPs, and ideal/non-ideal backhaul may beconfigured among the multiple TRPs. FIG. 14 is shown just for theconvenience of description, and not intended to limit the scope of thepresent disclosure. Furthermore, a part of step(s) shown in FIG. 14 maybe omitted depending on a situation and/or configuration.

Hereinafter, the description is described based on “TRP”, but asdescribed above, “TRP” may be substituted and applied by the expressionsuch as a panel, an antenna array, a cell (e.g., macro cell/smallcell/pico cell, etc.), a TP (transmission point), a base station (gNB,etc.). In addition, as described above, the TRP may be distinguishedaccording to information (e.g., index or ID) for a CORESET group (orCORESET pool). In one example, in the case that a single UE isconfigured to perform transmission/reception with multiple TRPs (orcells), this may mean that multiple CORESET groups (or CORESET pools)may be configured for the UE. A configuration for the CORESET group (orCORESET pool) may be performed through higher layer signaling (e.g., RRCsignaling).

The UE may receive Downlink Control Information (DCI) (step S1410). TheDCI may be transmitted through a control channel (e.g., PDCCH).

The DCI may include i) a transmission configuration indication (TCI)field and ii) an antenna port field. For example, based on the TCIfield, a plurality of TCI states may be indicated. In addition, based onthe antenna port field, DM-RS ports of a plurality of CDM groups may beindicated. For example, the number of layers associated with each CDMgroup may be differently configured.

For example, a plurality of state information related to a combinationof the CDM group and the DMRS port may be predefined, and specific stateinformation (or value) among the plurality of state information may beindicated through the antenna port field of DCI. In one example, thestate information may mean DMRS port related information (e.g., 3gppTS38.212 Table 7.3.1.2.2-1/2/3/4, etc.).

For example, the DCI may include CRC (cyclic redundancy check) scrambledby a specific RNTI (Radio Network Temporary Identifier). In one example,the specific RNTI may be MCS-C-RNTI (modulation coding scheme cellRNTI). That is, the DCI may be associated with MCS-C-RNTI. In oneexample, in the case that the UE receives the DCI including CRCscrambled by MCS-C-RNTI, the UE may identify that URLLC operation isperformed from the BS (or multiple MTRPs).

For example, based on the number of TCI states indicated through a TCIfield in the DCI, it may be indicated/configured that single-user (UE)dedicated DMRS port combination may be used for multiple-user (UE)usage. Alternatively, in the case that a plurality of TCI states isactivated on one or more code points among the code points correspondingto a TCI state field in the DCI, it may be indicated/configured thatsingle-user (UE) dedicated DMRS port combination may be used formultiple-user (UE) usage. Accordingly, information representing thatsingle-UE dedicated DMRS ports may be used by another UE (i.e., whetherSU dedicated DMRS port combination is operable for MU usage (whether itis activated)) may be received through higher layer signaling.

For example, the operation of the UE (100/200 shown in FIG. 16 to FIG.20) to receive DL control information of step S1420 described above maybe implemented by the apparatus shown in FIG. 16 to FIG. 20 to bedescribed below. For example, referring to FIG. 17, one or moreprocessors 102 may control one or more transceivers 106 and/or one ormore memories 104 to receive the DCI, and the one or more transceivers106 may receive the DCI.

The UE may receive a Physical downlink shared channel (PDSCH) scheduledbased on the DCI (step S1420). In addition, the UE may decode the PDSCH.For example, the PDSCH may be received after a specific offset from thereception timing of the DCI. For example, the procedure of receiving anddecoding the PDSCH may be performed based on the proposed method (e.g.,Proposal 1/2/3/4/5, etc.). The UE may know the number of CDM groups andthe configuration of the DMRS port that correspond to the antenna portfield of the DCI and may decode the PDSCH.

For example, it is assumed that based on the TCI field, multiple TCIstates are indicated, and based on the antenna port related information,DMRS ports of a plurality of CDM groups are indicated. Based on anindication order of the DMRS ports, orders of a plurality of CDM groupsmay be determined, and according to the determined orders of the CDMgroups, the multiple TCI states may be sequentially corresponded. Thefirst TCI state of the multiple TCI states may correspond to a CDM groupincluding the first DMRS port based on the indication order of the DMRSports.

In other words, based on the indication order of the DMRS ports, thefirst TCI state of the plurality of TCI states may correspond to a CDMgroup of the first DMRS port. In addition, the TCI states except thefirst TCI state may correspond to other CDM group except the CDM groupincluding the first DMRS port. Accordingly, the DMRS ports included inthe CDM group including the first DMRS port may be in QCL (Quasi colocation) relation with the reference signal related to the first TCIstate.

For example, the mapping scheme of the TCI state may applied to the casethat two codewords are transmitted/received as well as the case that onecodeword is transmitted/received through the data channel.

In still another example, in the case that the DCI is associated withMCS-C-RNTI, the DM-RS ports may correspond to the same DCI state. Basedon the condition that URLLC operation and multiple TCI states areindicated to the UE, each TCI state may correspond to a specificresource (e.g., at least one of time resource or frequency resource),and all DMRS ports indicated to the UE may correspond to the same TCIstate.

The DMRS ports may be mapped to layers. For example, regardless of theorder in which DMRS ports are indicated, the DMRS ports may besequentially mapped to the layers based on indexes of the DM-RS ports.Alternatively, the DMRS ports may be sequentially mapped to the layersbased on indication orders.

In addition, in the case that the data channel includes two codewords,the number of DMRS ports of the CDM group including the first DMRS portand the number of DMRS ports of the other CDM group may be determined tobe a specific number based on the total number of layers.

For example, based on the condition that URLLC operation and multipleTCI states are indicated to the UE, the UE may decode a PDSCH based onspecific DMRS port related information. The specific DMRS port relatedinformation may be 3gpp TS38.212 Table 7.3.1.2.2-1/2/3/4. Alternatively,a DMRS table configured with a subset of 3gpp TS38.212 Table7.3.1.2.2-1/2/3/4 may be defined, and the UE may decode a PDSCH based onthe subset. The subset may be configured except a DMRS port combinationfor the number of layers that exceeds a specific number of layers. Inaddition, a bit width for indicating the subset may be narrower than theconventional bit width, and the reduced bit width may be used forindicating URLLC operation scheme (e.g., SDM, FDM, or TDM).

For example, the operation of the UE (100/200 shown in FIG. 16 to FIG.20) to receive the PDSCH of step S1420 described above may beimplemented by the apparatus shown in FIG. 16 to FIG. 20 to be describedbelow. For example, referring to FIG. 17, one or more processors 102 maycontrol one or more transceivers 106 and/or one or more memories 104 toreceive the PDSCH, and the one or more transceivers 106 may receive thePDSCH.

Although it is not shown in FIG. 14, the UE may also receive theconfiguration information. The configuration information may be receivedthrough higher layer signaling (e.g., RRC or MAC CE, etc.). In addition,the operation of receiving the configuration information may beperformed before the operation of receiving the DCI of step S1410.

For example, the configuration information may include information ofconfiguring such that a DMRS port combination used for single-user isalso used for multiple-user among the predefined DMRS port relatedinformation. Alternatively, the configuration information may include aconfiguration for URLLC transmission. In one example, the configurationinformation may include a parameter (e.g., pdsch-AggregationFactor)related to a repetition number of the data, and URLLC transmission maybe configured based on the parameter.

FIG. 15 illustrates an example of data transmission/reception operationflowchart of a Base Station (BS) to which the methods (e.g., Proposal1/2/3/4/5, etc.) proposed in the present disclosure may be applied. FIG.15 is shown just for the convenience of description, and not intended tolimit the scope of the present disclosure. Furthermore, a part ofstep(s) shown in FIG. 15 may be omitted depending on a situation and/orconfiguration.

The BS may collectively mean an object that performs datatransmission/reception with the UE. For example, the BS may include oneor more TPs (Transmission Points), one or more TRPs (Transmission andReception Points), and the like. Furthermore, the TP and/or TRP mayinclude a panel, a transmission and reception unit, and the like of theBS. In addition, as described above, the TRP may be distinguishedaccording to information (e.g., index or ID) for a CORESET group (orCORESET pool). In one example, in the case that a single UE isconfigured to perform transmission/reception with multiple TRPs (orcells), this may mean that multiple CORESET groups (or CORESET pools)may be configured for the UE. A configuration for the CORESET group (orCORESET pool) may be performed through higher layer signaling (e.g., RRCsignaling).

The BS may transmit the configuration information (step S1510). Theconfiguration information may be received through higher layer signaling(e.g., RRC or MAC CE, etc.). The configuration information may includethe DMRS related configuration, the TCI state related configuration, andthe like.

For example, the configuration information may include information ofconfiguring such that a DMRS port combination used for single-user isalso used for multiple-user among the predefined DMRS port relatedinformation. Alternatively, the configuration information may include aconfiguration for URLLC transmission. In one example, the configurationinformation may include a parameter (e.g., pdsch-AggregationFactor)related to a repetition number of the data, and URLLC transmission maybe configured based on the parameter.

For example, the operation of the BS (100/200 shown in FIG. 16 to FIG.20) to transmit the configuration information of step S1510 describedabove may be implemented by the apparatus shown in FIG. 16 to FIG. 20 tobe described below. For example, referring to FIG. 17, one or moreprocessors 102 may control one or more transceivers 106 and/or one ormore memories 104 to transmit the configuration information, and the oneor more transceivers 106 may transmit the configuration information.

The BS may transmit Downlink Control Information (DCI) to the UE (stepS1520). The DCI may be transmitted through a control channel (e.g.,PDCCH).

The DCI may include i) a transmission configuration indication (TCI)field and ii) an antenna port field. For example, based on the TCIfield, a plurality of TCI states may be indicated. In addition, based onthe antenna port field, DM-RS ports of a plurality of CDM groups may beindicated. For example, the number of layers associated with each CDMgroup may be differently configured.

For example, based on an indication order of the DMRS ports, orders of aplurality of CDM groups may be determined, and according to thedetermined orders of the CDM groups, the multiple TCI states may besequentially corresponded. The first TCI state of the multiple TCIstates may correspond to a CDM group including the first DMRS port basedon the indication order of the DMRS ports.

In other words, based on the indication order of the DMRS ports, thefirst TCI state of the plurality of TCI states may correspond to a CDMgroup of the first DMRS port. In addition, the TCI states except thefirst TCI state may correspond to other CDM group except the CDM groupincluding the first DMRS port. Accordingly, the DMRS ports included inthe CDM group including the first DMRS port may be in QCL (Quasi colocation) relation with the reference signal related to the first TCIstate.

For example, a plurality of state information related to a combinationof the CDM group and the DMRS port may be predefined, and specific stateinformation (or value) among the plurality of state information may beindicated through the antenna port field of DCI. For example, the BS mayconfigure the number of CDM groups and the configuration of the DMRSport related to encoding of the PDSCH through a value of the antennaport field of the DCI.

For example, the DCI may include CRC (cyclic redundancy check) scrambledby a specific RNTI (Radio Network Temporary Identifier). In one example,the specific RNTI may be MCS-C-RNTI (modulation coding scheme cellRNTI). In one example, in the case that the BS may transmit the DCIincluding CRC scrambled by MCS-C-RNTI to the UE to configure URLLCoperation.

For example, based on the number of TCI states indicated through a TCIfield in the DCI, it may be indicated/configured that single-user (UE)dedicated DMRS port combination may be used for multiple-user (UE)usage. Alternatively, in the case that a plurality of TCI states isactivated on one or more code points among the code points correspondingto a TCI state field in the DCI, it may be indicated/configured thatsingle-user (UE) dedicated DMRS port combination may be used formultiple-user (UE) usage.

For example, the operation of the BS (100/200 shown in FIG. 16 to FIG.20) to transmit DL control information of step S1520 described above maybe implemented by the apparatus shown in FIG. 16 to FIG. 20 to bedescribed below. For example, referring to FIG. 17, one or moreprocessors 102 may control one or more transceivers 106 and/or one ormore memories 104 to transmit the DCI, and the one or more transceivers106 may transmit the DCI to the UE.

The BS may transmit the Physical downlink shared channel (PDSCH) to theUE (step S1530). For example, the procedure that the BS encodes andtransmits the PDSCH to the UE may be performed based on the proposedmethod (e.g., Proposal 1/2/3/4/5, etc.).

For example, the PDSCH may be mapped to layers and transmitted. Forexample, regardless of the order in which DMRS ports are indicated, theDMRS ports may be sequentially mapped to the layers based on indexes ofthe DM-RS ports. In addition, the PDSCH may be transmitted according tothe DMRS port related configuration/indication of the proposed method(e.g., Proposal 1/2/3/4/5, etc.).

For example, the operation of the BS (100/200 shown in FIG. 16 to FIG.20) to transmit the PDSCH to the UE of step S1430 described above may beimplemented by the apparatus shown in FIG. 16 to FIG. 20 to be describedbelow. For example, referring to FIG. 17, one or more processors 102 maycontrol one or more transceivers 106 and/or one or more memories 104 totransmit the PDSCH, and the one or more transceivers 106 may transmitthe PDSCH to the UE.

As described above, the Network side/UE signaling and the operation(e.g., Proposal 1/2/3/4/5, FIG. 13, FIG. 15, etc.) described above maybe implemented by the apparatus (e.g., FIG. 16 to FIG. 20) to bedescribed below. For example, the Network side (e.g., TRP 1/TRP 2) maycorrespond to a first wireless apparatus, and the UE may correspond to asecond wireless apparatus. In some cases, the opposite case may also beconsidered. For example, the first apparatus (e.g., TRP 1 and the secondapparatus (e.g., TRP 2) may correspond to a first wireless apparatus,and the UE may correspond to a second wireless apparatus. In some cases,the opposite case may also be considered.

For example, the Network side/UE signaling and the operation (e.g.,Proposal 1/2/3/4/5, FIG. 13, FIG. 15, etc.) described above may beprocessed by one or more processors (e.g., 102 and 202), and the Networkside/UE signaling and the operation (e.g., Proposal 1/2/3/4/5, FIG. 13,FIG. 15, etc.) described above may be stored in one or memories (e.g.,104 and 204) in a command/program (e.g., instruction, executable code)form to drive one or more processors (e.g., 102 and 202) shown in FIG.16 to FIG. 20.

Example of Communication System to which Present Disclosure is Applied

Although not limited thereto, but various descriptions, functions,procedures, proposals, methods, and/or operation flowcharts of thepresent disclosure, which are disclosed in this document may be appliedto various fields requiring wireless communications/connections (e.g.,5G) between devices.

Hereinafter, the communication system will be described in more detailwith reference to drawings. In the following drawings/descriptions, thesame reference numerals will refer to the same or corresponding hardwareblocks, software blocks, or functional blocks if not differentlydescribed.

FIG. 16 illustrates a communication system applied to the presentdisclosure.

Referring to FIG. 16, a communication system 1 applied to the presentdisclosure includes a wireless device, a BS, and a network. Here, thewireless device may mean a device that performs communication by using awireless access technology (e.g., 5G New RAT (NR) or Long Term Evolution(LTE)) and may be referred to as a communication/wireless/5G device.Although not limited thereto, the wireless device may include a robot100 a. vehicles 100 b-1 and 100 b-2, an eXtended Reality (XR) device 100c, a hand-held device 100 d, a home appliance 100 e, an Internet ofThing (IoT) device 100 f, and an AI device/server 400. For example, thevehicle may include a vehicle with a wireless communication function, anautonomous driving vehicle, a vehicle capable of performinginter-vehicle communication, and the like. Here, the vehicle may includean Unmanned Aerial Vehicle (UAV) (e.g., drone). The XR device mayinclude an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality(MR) device and may be implemented as a form such as a head-mounteddevice (HMD), a head-up display (HUD) provided in the vehicle, atelevision, a smart phone, a computer, a wearable device, a homeappliance device, digital signage, a vehicle, a robot, etc. Thehand-held device may include the smart phone, a smart pad, a wearabledevice (e.g., a smart watch, a smart glass), a computer (e.g., anotebook, etc.), and the like. The home appliance device may include aTV, a refrigerator, a washing machine, and the like. The IoT device mayinclude a sensor, a smart meter, and the like. For example, the BS andthe network may be implemented even the wireless device and a specificwireless device 200 a may operate an eNB/network node for anotherwireless device.

The wireless devices 100 a to 100 f may be connected to a network 300through a BS 200. An artificial intelligence (AI) technology may beapplied to the wireless devices 100 a to 100 f and the wireless devices100 a to 100 f may be connected to an AI server 400 through the network300. The network 300 may be configured by using a 3G network, a 4G(e.g., LTE) network, or a 5G (e.g., NR) network. The wireless devices100 a to 100 f may communicate with each other through the BS200/network 300, but may directly communicate with each other withoutgoing through the BS/network (sidelink communication). For example, thevehicles 100 b-1 and 100 b-2 may perform direct communication (e.g.,Vehicle to Vehicle (V2V)/Vehicle to everything (V2X) communication).Further, the IoT device (e.g., sensor) may perform direct communicationwith other IoT devices (e.g., sensor) or other wireless devices 100 a to100 f.

Wireless communications/connections 150 a, 150 b, and 150 c may be madebetween the wireless devices 100 a to 100 f and the BS 200 and betweenthe BS 200 and the BS 200. Here, the wireless communication/connectionmay be made through various wireless access technologies (e.g., 5G NR)such as uplink/downlink communication 150 a, sidelink communication 150b (or D2D communication), and inter-BS communication 150 c (e.g., relay,Integrated Access Backhaul (IAB). The wireless device and the BS/thewireless device and the BS and the BS may transmit/receive radio signalsto/from each other through wireless communications/connections 150 a,150 b, and 150 c. For example, the wireless communications/connections150 a, 150 b, and 150 c may transmit/receive signals through variousphysical channels. To this end, based on various proposals of thepresent disclosure, at least some of various configuration informationsetting processes, various signal processing processes (e.g., channelencoding/decoding, modulation/demodulation, resource mapping/demapping,etc.), a resource allocation process, and the like fortransmission/reception of the radio signal may be performed.

Example of Wireless Device to which Present Disclosure is Applied

FIG. 17 illustrates a wireless device which may be applied to thepresent disclosure.

Referring to FIG. 17, a first wireless device 100 and a second wirelessdevice 200 may transmit/receive radio signals through various wirelessaccess technologies (e.g., LTE and NR). Here, the first wireless device100 and the second wireless device 200 may correspond to a wirelessdevice 100 x and a BS 200 and/or a wireless device 100 x and a wirelessdevice 100 x of FIG. 16.

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor 102 maycontrol the memory 104 and/or the transceiver 106 and may be configuredto implement descriptions, functions, procedures, proposals, methods,and/or operation flows disclosed in the present disclosure. For example,the processor 102 may process information in the memory 104 and generatea first information/signal and then transmit a radio signal includingthe first information/signal through the transceiver 106. Further, theprocessor 102 may receive a radio signal including a secondinformation/signal through the transceiver 106 and then store in thememory 104 information obtained from signal processing of the secondinformation/signal. The memory 104 may connected to the processor 102and store various information related to an operation of the processor102. For example, the memory 104 may store a software code includinginstructions for performing some or all of processes controlled by theprocessor 102 or performing the descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in the presentdisclosure. Here, the processor 102 and the memory 104 may be a part ofa communication modem/circuit/chip designated to implement the wirelesscommunication technology (e.g., LTE and NR). The transceiver 106 may beconnected to the processor 102 and may transmit and/or receive the radiosignals through one or more antennas 108. The transceiver 106 mayinclude a transmitter and/or a receiver. The transceiver 106 may be usedmixedly with a radio frequency (RF) unit. In the present disclosure, thewireless device may mean the communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor 202may control the memory 204 and/or the transceiver 206 and may beconfigured to implement descriptions, functions, procedures, proposals,methods, and/or operation flows disclosed in the present disclosure. Forexample, the processor 202 may process information in the memory 204 andgenerate a third information/signal and then transmit a radio signalincluding the third information/signal through the transceiver 206.Further, the processor 202 may receive a radio signal including a fourthinformation/signal through the transceiver 206 and then store in thememory 204 information obtained from signal processing of the fourthinformation/signal. The memory 204 may connected to the processor 202and store various information related to an operation of the processor202. For example, the memory 204 may store a software code includinginstructions for performing some or all of processes controlled by theprocessor 202 or performing the descriptions, functions, procedures,proposals, methods, and/or operation flowcharts disclosed in the presentdisclosure. Here, the processor 202 and the memory 204 may be a part ofa communication modem/circuit/chip designated to implement the wirelesscommunication technology (e.g., LTE and NR). The transceiver 206 may beconnected to the processor 202 and may transmit and/or receive the radiosignals through one or more antennas 208. The transceiver 206 mayinclude a transmitter and/or a receiver and the transceiver 206 may bemixed with the RF unit. In the present disclosure, the wireless devicemay mean the communication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described in more detail. Although not limited thereto, one or moreprotocol layers may be implemented by one or more processors 102 and202. For example, one or more processors 102 and 202 may implement oneor more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). One or more processors 102 and 202 may generate one ormore protocol data units (PDUs) and/or one or more service data units(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operation flowcharts disclosed in the presentdisclosure. One or more processors 102 and 202 may generate a message,control information, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operation flowchartsdisclosed in the present disclosure. One or more processors 102 and 202may generate a signal (e.g., a baseband signal) including the PDU, theSDU, the message, the control information, the data, or the informationaccording to the function, the procedure, the proposal, and/or themethod disclosed in the present disclosure and provide the generatedsignal to one or more transceivers 106 and 206. One or more processors102 and 202 may receive the signal (e.g., baseband signal) from one ormore transceivers 106 and 206 and acquire the PDU, the SDU, the message,the control information, the data, or the information according to thedescriptions, functions, procedures, proposals, methods, and/oroperation flowcharts disclosed in the present disclosure.

One or more processors 102 and 202 may be referred to as a controller, amicrocontroller, a microprocessor, or a microcomputer. One or moreprocessors 102 and 202 may be implemented by hardware, firmware,software, or a combination thereof. As one example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in one or moreprocessors 102 and 202. The descriptions, functions, procedures,proposals, and/or operation flowcharts disclosed in the presentdisclosure may be implemented by using firmware or software and thefirmware or software may be implemented to include modules, procedures,functions, and the like. Firmware or software configured to perform thedescriptions, functions, procedures, proposals, and/or operationflowcharts disclosed in the present disclosure may be included in one ormore processors 102 and 202 or stored in one or more memories 104 and204 and driven by one or more processors 102 and 202. The descriptions,functions, procedures, proposals, and/or operation flowcharts disclosedin the present disclosure may be implemented by using firmware orsoftware in the form of a code, the instruction and/or a set form of theinstruction.

One or more memories 104 and 204 may be connected to one or moreprocessors 102 and 202 and may store various types of data, signals,messages, information, programs, codes, instructions, and/or commands.One or more memories 104 and 204 may be configured by a ROM, a RAM, anEPROM, a flash memory, a hard drive, a register, a cache memory, acomputer reading storage medium, and/or a combination thereof. One ormore memories 104 and 204 may be positioned inside and/or outside one ormore processors 102 and 202. Further, one or more memories 104 and 204may be connected to one or more processors 102 and 202 through varioustechnologies such as wired or wireless connection.

One or more transceivers 106 and 206 may transmit to one or more otherdevices user data, control information, a wireless signal/channel, etc.,mentioned in the methods and/or operation flowcharts of the presentdisclosure. One or more transceivers 106 and 206 may receive from one ormore other devices user data, control information, a wirelesssignal/channel, etc., mentioned in the descriptions, functions,procedures, proposals, methods, and/or operation flowcharts disclosed inthe present disclosure. For example, one or more transceivers 106 and206 may be connected to one or more processors 102 and 202 and transmitand receive the radio signals. For example, one or more processors 102and 202 may control one or more transceivers 106 and 206 to transmit theuser data, the control information, or the radio signal to one or moreother devices. Further, one or more processors 102 and 202 may controlone or more transceivers 106 and 206 to receive the user data, thecontrol information, or the radio signal from one or more other devices.Further, one or more transceivers 106 and 206 may be connected to one ormore antennas 108 and 208 and one or more transceivers 106 and 206 maybe configured to transmit and receive the user data, controlinformation, wireless signal/channel, etc., mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperation flowcharts disclosed in the present disclosure through one ormore antennas 108 and 208. In the present disclosure one or moreantennas may be a plurality of physical antennas or a plurality oflogical antennas (e.g., antenna ports). One or more transceivers 106 and206 may convert the received radio signal/channel from an RF band signalto a baseband signal in order to process the received user data, controlinformation, radio signal/channel, etc., by using one or more processors102 and 202. One or more transceivers 106 and 206 may convert the userdata, control information, radio signal/channel, etc., processed byusing one or more processors 102 and 202, from the baseband signal intothe RF band signal. To this end, one or more transceivers 106 and 206may include an (analog) oscillator and/or filter.

Example of Signal Processing Circuit to which Present Disclosure isApplied

FIG. 18 illustrates a signal processing circuit for a transmit signal.

Referring to FIG. 18 a signal processing circuit 1000 may include ascrambler 1010, a modulator 1020, a layer mapper 1030, a precoder 1040,a resource mapper 1050, and a signal generator 1060. Although notlimited thereto, an operation/function of FIG. 18 may be performed bythe processors 102 and 202 and/or the transceivers 106 and 206 of FIG.17. Hardware elements of FIG. 18 may be implemented in the processors102 and 202 and/or the transceivers 106 and 206 of FIG. 17. For example,blocks 1010 to 1060 may be implemented in the processors 102 and 202 ofFIG. 17. Further, blocks 1010 to 1050 may be implemented in theprocessors 102 and 202 of FIG. 17 and the block 1060 may be implementedin the transceivers 106 and 206 of FIG. 17.

A codeword may be transformed into a radio signal via the signalprocessing circuit 1000 of FIG. 18. Here, the codeword is an encoded bitsequence of an information block. The information block may includetransport blocks (e.g., a UL-SCH transport block and a DL-SCH transportblock). The radio signal may be transmitted through various physicalchannels (e.g., PUSCH and PDSCH).

Specifically, the codeword may be transformed into a bit sequencescrambled by the scrambler 1010. A scramble sequence used for scramblingmay be generated based on an initialization value and the initializationvalue may include ID information of a wireless device. The scrambled bitsequence may be modulated into a modulated symbol sequence by themodulator 1020. A modulation scheme may include pi/2-Binary Phase ShiftKeying (pi/2-BPSK), m-Phase Shift Keying (m-PSK), m-Quadrature AmplitudeModulation (m-QAM), etc. A complex modulated symbol sequence may bemapped to one or more transport layers by the layer mapper 1030.Modulated symbols of each transport layer may be mapped to acorresponding antenna port(s) by the precoder 1040 (precoding). Output zof the precoder 1040 may be obtained by multiplying output y of thelayer mapper 1030 by precoding matrix W of N*M. Here, N represents thenumber of antenna ports and M represents the number of transport layers.Here, the precoder 1040 may perform precoding after performing transformprecoding (e.g., DFT transform) for complex modulated symbols. Further,the precoder 1040 may perform the precoding without performing thetransform precoding.

The resource mapper 1050 may map the modulated symbols of each antennaport to a time-frequency resource. The time-frequency resource mayinclude a plurality of symbols (e.g., CP-OFDMA symbol and DFT-s-OFDMAsymbol) in a time domain and include a plurality of subcarriers in afrequency domain. The signal generator 1060 may generate the radiosignal from the mapped modulated symbols and the generated radio signalmay be transmitted to another device through each antenna. To this end,the signal generator 1060 may include an Inverse Fast Fourier Transform(IFFT) module, a Cyclic Prefix (CP) insertor, a Digital-to-AnalogConverter (DAC), a frequency uplink converter, and the like.

A signal processing process for a receive signal in the wireless devicemay be configured in the reverse of the signal processing process (1010to 1060) of FIG. 18. For example, the wireless device (e.g., 100 or 200of FIG. 17) may receive the radio signal from the outside through theantenna port/transceiver. The received radio signal may be transformedinto a baseband signal through a signal reconstructer. To this end, thesignal reconstructer may include a frequency downlink converter, ananalog-to-digital converter (ADC), a CP remover, and a Fast FourierTransform (FFT) module. Thereafter, the baseband signal may bereconstructed into the codeword through a resource demapper process, apostcoding process, a demodulation process, and a de-scrambling process.The codeword may be reconstructed into an original information block viadecoding. Accordingly, a signal processing circuit (not illustrated) forthe receive signal may include a signal reconstructer, a resourcedemapper, a postcoder, a demodulator, a descrambler, and a decoder.

Utilization Example of Wireless Device to Which Present Disclosure isApplied

FIG. 19 illustrates another example of a wireless device applied to thepresent disclosure. The wireless device may be implemented as varioustypes according to a use example/service (see FIG. 16).

Referring to FIG. 19, wireless devices 100 and 200 may correspond to thewireless devices 100 and 200 of FIG. 17 and may be constituted byvarious elements, components, units, and/or modules. For example, thewireless devices 100 and 200 may include a communication unit 110, acontrol unit 120, and a memory unit 130, and an additional element 140.The communication unit may include a communication circuit 112 and atransceiver(s) 114. For example, the communication circuit 112 mayinclude one or more processors 102 and 202 and/or one or more memories104 and 204 of FIG. 17. For example, the transceiver(s) 114 may includeone or more transceivers 106 and 206 and/or one or more antennas 108 and208 of FIG. 17. The control unit 120 is electrically connected to thecommunication unit 110, the memory unit 130, and the additional element140 and controls an overall operation of the wireless device. Forexample, the control unit 120 may an electrical/mechanical operation ofthe wireless device based on a program/code/instruction/informationstored in the memory unit 130. Further, the control unit 120 maytransmit the information stored in the memory unit 130 to the outside(e.g., other communication devices) through the communication unit 110via a wireless/wired interface or store information received from theoutside (e.g., other communication devices) through the wireless/wiredinterface through the communication unit 110.

The additional element 140 may be variously configured according to thetype of wireless device. For example, the additional element 140 mayinclude at least one of a power unit/battery, an input/output (I/O)unit, a driving unit, and a computing unit. Although not limitedthereto, the wireless device may be implemented as a form such as therobot 100 a of FIG. 16, the vehicles 100 b-1 and 100 b-2 of FIG. 16, theXR device 100 c of FIG. 16, the portable device 100 d of FIG. 16, thehome appliance 100 e of FIG. 16, the IoT device 100 f of FIG. 16, adigital broadcasting terminal, a hologram device, a public safetydevice, an MTC device, a medical device, a fintech device (or financialdevice), a security device, a climate/environment device, an AIserver/device 400 of FIG. 16, the BS 200 of FIG. 16, a network node,etc. The wireless device may be movable or may be used at a fixed placeaccording to a use example/service.

In FIG. 19, all of various elements, components, units, and/or modulesin the wireless devices 100 and 200 may be interconnected through thewired interface or at least may be wirelessly connected through thecommunication unit 110. For example, the control unit 120 and thecommunication 110 in the wireless devices 100 and 200 may be wiredlyconnected and the control unit 120 and the first unit (e.g., 130 or 140)may be wirelessly connected through the communication unit 110. Further,each element, component, unit, and/or module in the wireless devices 100and 200 may further include one or more elements. For example, thecontrol unit 120 may be constituted by one or more processor sets. Forexample, the control unit 120 may be configured a set of a communicationcontrol processor, an application processor, an electronic control unit(ECU), a graphic processing processor, a memory control processor, etc.As another example, the memory 130 may be configured as a random accessmemory (RAM), a dynamic RAM (DRAM), a read only memory (ROM), a flashmemory, a volatile memory, a non-volatile memory, and/or combinationsthereof.

Example of Hand-Held Device to which Present Disclosure is Applied

FIG. 20 illustrates a hand-held device applied to the presentdisclosure. The hand-held device may include a smart phone, a smart pad,a wearable device (e.g., a smart watch, a smart glass), and a hand-heldcomputer (e.g., a notebook, etc.). The hand-held device may be referredto as a Mobile Station (MS), a user terminal (UT), a Mobile SubscriberStation (MSS), a Subscriber Station (SS), an Advanced Mobile Station(AMS), or a Wireless terminal (WT).

Referring to FIG. 20, a hand-held device 100 may include an antenna unit108, a communication unit 110, a control unit 120, a memory unit 130, apower supply unit 140 a, an interface unit 140 b, and an input/outputunit 140 c. The antenna unit 108 may be configured as a part of thecommunication unit 110. The blocks 110 to 130/140 a to 140 c correspondto the blocks 110 to 130/140 of FIG. 19, respectively.

The communication unit 110 may transmit/receive a signal (e.g., data, acontrol signal, etc.) to/from another wireless device and BSs. Thecontrol unit 120 may perform various operations by controllingcomponents of the hand-held device 100. The control unit 120 may includean Application Processor (AP). The memory unit 130 may storedata/parameters/programs/codes/instructions required for driving thehand-held device 100. Further, the memory unit 130 may storeinput/output data/information, etc. The power supply unit 140 a maysupply power to the hand-held device 100 and include a wired/wirelesscharging circuit, a battery, and the like. The interface unit 140 b maysupport a connection between the hand-held device 100 and anotherexternal device. The interface unit 140 b may include various ports(e.g., an audio input/output port, a video input/output port) for theconnection with the external device. The input/output unit 140 c mayreceive or output a video information/signal, an audioinformation/signal, data, and/or information input from a user. Theinput/output unit 140 c may include a camera, a microphone, a user inputunit, a display unit 140 d, a speaker, and/or a haptic module.

As one example, in the case of data communication, the input/output unit140 c may acquire information/signal (e.g., touch, text, voice, image,and video) input from the user and the acquired information/signal maybe stored in the memory unit 130. The communication unit 110 maytransform the information/signal stored in the memory into the radiosignal and directly transmit the radio signal to another wireless deviceor transmit the radio signal to the eNB. Further, the communication unit110 may receive the radio signal from another wireless device or eNB andthen reconstruct the received radio signal into originalinformation/signal. The reconstructed information/signal may be storedin the memory unit 130 and then output in various forms (e.g., text,voice, image, video, haptic) through the input/output unit 140 c.

The embodiments described above are implemented by combinations ofcomponents and features of the present disclosure in predeterminedforms. Each component or feature should be considered selectively unlessspecified separately. Each component or feature may be carried outwithout being combined with another component or feature. Moreover, somecomponents and/or features are combined with each other and canimplement embodiments of the present disclosure. The order of operationsdescribed in embodiments of the present disclosure may be changed. Somecomponents or features of one embodiment may be included in anotherembodiment, or may be replaced by corresponding components or featuresof another embodiment. It is apparent that some claims referring tospecific claims may be combined with another claims referring to theclaims other than the specific claims to constitute the embodiment oradd new claims by means of amendment after the application is filed.

Embodiments of the present disclosure can be implemented by variousmeans, for example, hardware, firmware, software, or combinationsthereof. When embodiments are implemented by hardware, one embodiment ofthe present disclosure can be implemented by one or more applicationspecific integrated circuits (ASICs), digital signal processors (DSPs),digital signal processing devices (DSPDs), programmable logic devices(PLDs), field programmable gate arrays (FPGAs), processors, controllers,microcontrollers, microprocessors, and the like.

When embodiments are implemented by firmware or software, one embodimentof the present disclosure can be implemented by modules, procedures,functions, etc. performing functions or operations described above.Software code can be stored in a memory and can be driven by aprocessor. The memory is provided inside or outside the processor andcan exchange data with the processor by various well-known means.

It is apparent to those skilled in the art that the present disclosurecan be embodied in other specific forms without departing from essentialfeatures of the present disclosure. Accordingly, the aforementioneddetailed description should not be construed as limiting in all aspectsand should be considered as illustrative. The scope of the presentdisclosure should be determined by rational construing of the appendedclaims, and all modifications within an equivalent scope of the presentdisclosure are included in the scope of the present disclosure.

INDUSTRIAL APPLICABILITY

Although a method of transmitting and receiving PDSCH in a wirelesscommunication system of the present disclosure has been described withreference to an example applied to a 3GPP LTE/LTE-A system or a 5Gsystem (New RAT system), the scheme may be applied to various wirelesscommunication systems in addition to the 3GPP LTE/LTE-A system or 5Gsystem.

1. A method for receiving a phase tracking reference signal (PTRS) by auser equipment (UE) in a wireless communication system, the methodcomprising: receiving downlink control information (DCI), wherein a codepoint corresponding to one or more TCI states is indicated based on atransmission configuration indication (TCI) field of the DCI, andwherein a demodulation reference signal (DMRS) port is indicated basedon an antenna port field of the DCI; and receiving a PTRS which istransmitted through an antenna port associated with a specific DMRS portamong the DMRS port, wherein, based on i) a number of TCI statescorresponding to the code point being 2, ii) a number of CDM groupsincluding the DMRS port being 2, and iii) a maximum value of a number ofantenna ports through which the PTRS is transmitted being 2, the numberof antenna ports through which the PTRS is transmitted is determined as2.
 2. The method of claim 1, wherein, based on a maximum value of thenumber of antenna ports through which the PTRS is transmitted being 1,the number of antenna ports through which the PTRS is transmitted isdetermined as
 1. 3. The method of claim 1, wherein, based on a maximumvalue of the number of antenna ports through which the PTRS istransmitted being 2, the number of antenna ports through which the PTRSis transmitted is determined as 1 or
 2. 4. The method of claim 2,further comprising: receiving, from the base station, the PTRS relatedconfiguration information including information on the maximum value ofthe number of antenna ports through which the PTRS is transmitted. 5.The method of claim 4, wherein the maximum value of the number ofantenna ports through which the PTRS is transmitted is determined basedon the information on the maximum value of the number of antenna portsthrough which the PTRS is transmitted.
 6. The method of claim 3,wherein, based on i) the number of TCI states corresponding to the codepoint being 2 and ii) the number of CDM groups including the DMRS portbeing 1, the number of antenna ports through which the PTRS istransmitted is determined as
 1. 7. The method of claim 3, wherein, basedon i) the number of TCI states corresponding to the code point being 2,ii) the number of CDM groups including the DMRS port being 1, and iii)the maximum value of the number of antenna ports through which the PTRSis transmitted being 2, the number of antenna ports through which thePTRS is transmitted is determined as
 1. 8-20. (canceled)
 21. A userequipment (UE) receiving a phase tracking reference signal (PTRS) in awireless communication system, the terminal comprising: one or moretransceivers; one or more processors; and one or more memories forstoring instructions for operations executed by the one or moreprocessors and being coupled to the one or more processors; wherein theoperations comprises: receiving downlink control information (DCI),wherein a code point corresponding to one or more TCI states isindicated based on a transmission configuration indication (TCI) fieldof the DCI, and wherein a demodulation reference signal (DMRS) port isindicated based on an antenna port field of the DCI; and receiving aPTRS which is transmitted through an antenna port associated with aspecific DMRS port among the DMRS port, wherein, based on i) a number ofTCI states corresponding to the code point being 2, ii) a number of CDMgroups including the DMRS port being 2, and iii) a maximum value of anumber of antenna ports through which the PTRS is transmitted being 2,the number of antenna ports through which the PTRS is transmitted isdetermined as
 2. 22. An apparatus comprising one or more memories andone or more processors operatively coupled to the one or more memories,the apparatus comprising: wherein the one or more processors controlsthe apparatus to: receive downlink control information (DCI), wherein acode point corresponding to one or more TCI states is indicated based ona transmission configuration indication (TCI) field of the DCI, andwherein a demodulation reference signal (DMRS) port is indicated basedon an antenna port field of the DCI; and receive a PTRS which istransmitted through an antenna port associated with a specific DMRS portamong the DMRS port, wherein, based on i) a number of TCI statescorresponding to the code point being 2, ii) a number of CDM groupsincluding the DMRS port being 2, and iii) a maximum value of a number ofantenna ports through which the PTRS is transmitted being 2, the numberof antenna ports through which the PTRS is transmitted is determined as2.